Impaired glucose regulation, elevated glycated haemoglobin and cardiac ischaemic events in vascular surgery patients.

AIMS: Cardiac morbidity and mortality is high in patients undergoing high-risk surgery. This study investigated whether impaired glucose regulation and elevated glycated haemoglobin (HbA(1c)) levels are associated with increased cardiac ischaemic events in vascular surgery patients. METHODS: Baseline glucose and HbA(1c) were measured in 401 vascular surgery patients. Glucose < 5.6 mmol/l was defined as normal. Fasting glucose 5.6-7.0 mmol/l or random glucose 5.6-11.1 mmol/l was defined as impaired glucose regulation. Fasting glucose > or = 7.0 or random glucose > or = 11.1 mmol/l was defined as diabetes. Perioperative ischaemia was identified by 72-h Holter monitoring. Troponin T was measured on days 1, 3 and 7 and before discharge. Cardiac death or Q-wave myocardial infarction was noted at 30-day and longer-term follow-up (mean 2.5 years). RESULTS: Mean (+/- sd) level for glucose was 6.3 +/- 2.3 mmol/l and for HbA(1c) 6.2 +/- 1.3%. Ischaemia, troponin release, 30-day and long-term cardiac events occurred in 27, 22, 6 and 17%, respectively. Using subjects with normal glucose levels as the reference category, multivariate analysis revealed that patients with impaired glucose regulation and diabetes were at 2.2- and 2.6-fold increased risk of ischaemia, 3.8- and 3.9-fold for troponin release, 4.3- and 4.8-fold for 30-day cardiac events and 1.9- and 3.1-fold for long-term cardiac events. Patients with HbA(1c) > 7.0% (n = 63, 16%) were at 2.8-fold, 2.1-fold, 5.3-fold and 5.6-fold increased risk for ischaemia, troponin release, 30-day and long-term cardiac events, respectively. CONCLUSIONS: Impaired glucose regulation and elevated HbA(1c) are risk factors for cardiac ischaemic events in vascular surgery patients.

Time course of functional recovery of stunned and hibernating segments after surgical revascularization.

BACKGROUND: Recovery of function is possible in patients with ischemic cardiomyopathy when left ventricular dysfunction is caused by stunning or hibernation. It is plausible that recovery of function after revascularization may take a longer time in hibernating myocardium compared with stunned myocardium. Accordingly, the time courses of functional recovery in hibernating and stunned myocardium were compared. METHODS AND RESULTS: Patients (n=26) with ischemic cardiomyopathy undergoing surgical revascularization were studied; regional perfusion (resting (201)Tl single-photon emission CT), glucose utilization ((18)F-2-deoxyglucose single-photon emission CT), and contractile function (2D echocardiography) were assessed before revascularization. Dysfunctional segments with normal perfusion/glucose utilization were considered to be stunned, and dysfunctional segments with reduced perfusion/preserved glucose utilization were considered to be hibernating. Contractile function was reevaluated 3 months (early) and 14 months (late) after revascularization. Of the 266 dysfunctional segments, 57 (22%) were stunned, 62 (23%) were hibernating, and 147 (55%) were scar tissue. In stunned myocardium, contractile function improved significantly at 3 months, without further improvement at 14 months; 61% of the stunned segments improved at 3 months, and 9% improved at 14 months. In hibernating myocardium, contractile function improved at 3 months, with a further improvement at 14 months; 31% of the hibernating segments improved at 3 months, and 61% showed (additional) recovery at 14 months. CONCLUSIONS: Stunned myocardium is likely to demonstrate early recovery of function, whereas hibernating myocardium may take a longer time to (fully) recover in function after revascularization.

Dobutamine stress myocardial perfusion imaging.

In patients with limited exercise capacity and (relative) contraindications to direct vasodilators such as dipyridamole or adenosine, dobutamine stress nuclear myocardial perfusion imaging (DSMPI) represents an alternative, exercise-independent stress modality for the detection of coronary artery disease (CAD). Nondiagnostic test results (absence of reversible perfusion defects with submaximal stress) do occur in approximately 10% of patients. Serious side effects during DSMPI are rare, with no death, myocardial infarction or ventricular fibrillation reported in three DSMPI safety reports for a total of 2,574 patients. On the basis of a total number of 1,014 patients reported in 20 studies, the sensitivity, specificity and accuracy of the test for the detection of CAD were 88%, 74% and 84%, respectively. Mean sensitivities for one-, two- and three-vessel disease were 84%, 95% and 100%, respectively. The sensitivity for detection of left circumflex CAD (50%) was lower, compared with that for left anterior descending CAD (68%) and right CAD (88%). The sensitivity of predicting multivessel disease by multiregion perfusion abnormalities varied widely, from 44% to 89%, although specificity was excellent in all studies (89% to 94%). In direct diagnostic comparisons, DSMPI was more sensitive, but less specific, than dobutamine stress echocardiography and comparable with direct vasodilator myocardial perfusion imaging. In the largest prognostic study, patients with a normal DSMPI study had an annual hard event rate less than 1%. An ischemic scan pattern provided independent prognostic value, with a direct relationship between the extent and severity of the perfusion defects and prognosis. In conclusion, DSMPI seems a safe and useful nonexercise-dependent stress modality to detect CAD and assess prognosis.

The significance of stress-induced ST segment depression in patients with inferior Q wave myocardial infarction.

OBJECTIVES: This study was conducted to evaluate the relationship between ST segment depression (STD) during dobutamine stress tests in different electrocardiogram (ECG) leads and myocardial ischemia assessed by simultaneous single photon emission computed tomography (SPECT) imaging in patients with inferior Q wave myocardial infarction. BACKGROUND: STD is a standard electrocardiographic sign of myocardial ischemia. Although STD may represent reciprocal changes in patients with previous myocardial infarction, studies of reciprocal changes during stress tests are scarce. METHODS: Dobutamine (up to 40 microg/kg/min) stress and rest myocardial perfusion scintigraphy using technetium SPECT imaging was performed in 125 patients >3 months after Q wave inferior myocardial infarction. The location of STD at the ECG was defined as anterior (V1-4), high lateral (I, aVL) and lateral (V5,6). Ischemia was defined as reversible perfusion abnormalities. RESULTS: STD occurred in the high lateral leads in 20 patients, in the anterior leads in 12 patients and in the lateral leads in 2 patients. ST segment elevation occurred in 25 patients in the inferior leads. High lateral STD was associated with inferior ST elevation in 16 patients (80%). There was a significant inverse linear correlation between the magnitude of ST segment shift from rest to peak stress in the inferior and the high lateral leads (r = -0.8, p < 0.0005), whereas no significant correlation was found between ST segment shift in the inferior and the anterior leads (r = -0.1, p = NS) or between the inferior and the lateral leads (r = 0.15, p = NS). Ischemia was detected in 45% of patients with and in 42% of patients without high lateral STD (p = NS). Patients with high lateral STD had a higher prevalence of fixed perfusion defects in the inferior wall (100% vs. 70%) and in the posterolateral wall (55% vs. 29%) compared with other patients (both p < 0.05). Ischemia was more prevalent in patients with anterior STD than without (75% vs. 39%, p < 0.05). CONCLUSIONS: In patients with inferior Q wave myocardial infarction, stress-induced STD in high lateral leads should be recognized as a reciprocal change for ST elevation in the inferior leads, and therefore, should be interpreted with the consideration of the significance of ST elevation if present, rather than being indicative of myocardial ischemia on its own. The STD found in the anterior leads appears to be a sign of myocardial ischemia. These findings should be considered in the definition of a positive ECG stress test and in establishing the criteria for the termination of stress test.

Prognostic stratification of diabetic patients by exercise echocardiography.

OBJECTIVES: The aim of this study was to assess the incremental value of exercise echocardiography for the risk stratification of diabetic patients. BACKGROUND: There are currently insufficient outcome data in diabetic patients to define the role of stress echocardiography as a prognostic tool. METHODS: We studied the prognostic value of exercise echocardiography in 563 patients with diabetes mellitus (mean age 64 +/- 11 years, 336 men) and known or suspected ischemic heart disease (IHD). RESULTS: Cardiac events occurred in 50 patients (cardiac death in 23 and nonfatal myocardial infarction [MI] in 27) during a median follow-up period of three years. Event rate was lower in patients with normal as compared to those with abnormal exercise echocardiography at one year (0% vs. 1.9%), three years (1.8% vs. 11.9%), and five years (7.6% vs. 23.3%), respectively (p = 0.0001). Patients with multivessel distribution of echocardiographic abnormalities had the highest event rate (2.9% at one year, 15.2% at three years, and 32.8% at five years). In an incremental multivariate analysis model, exercise echocardiography increased the chi-square of the clinical and exercise ECG model from 29 to 44.8 (p = 0.0001). CONCLUSIONS: Exercise echocardiography provides incremental data for risk stratification of diabetic patients with known or suspected IHD. Patients with a normal exercise echocardiogram have a low event rate. Patients with multivessel distribution of exercise echocardiographic abnormalities are at the highest risk of cardiac events, as one-third of these patients experience cardiac death or nonfatal MI during the five years following exercise echocardiography.

Prognostic value of dobutamine-atropine stress technetium-99m sestamibi perfusion scintigraphy in patients with chest pain.

OBJECTIVES: This study investigated the prognostic value of dobutamine-atropine technetium-99m (Tc-99m) sestamibi single-photon emission computed tomographic (SPECT) myocardial perfusion imaging. BACKGROUND: Dobutamine-atropine Tc-99m sestamibi SPECT imaging is an accurate method for the detection of coronary disease. However, the prognostic value of this stress modality has not been assessed. METHODS: Three hundred ninety-two consecutive patients with chest pain (mean [+/- SD] age 60 +/- 12 years; 220 men, 190 with a previous myocardial infarction) underwent a dobutamine-atropine Tc-99m sestamibi SPECT scintigraphic study. Patients were followed up for 22 +/- 13 months to determine the univariate and multivariate variables associated with hard cardiac events (cardiac death, nonfatal myocardial infarction), to define their event-free survival and to determine whether the extent and severity of reversible perfusion defects correlated with events. RESULTS: Forty-four patients (11%) had hard cardiac events. Multivariate models demonstrated that older age (odds ratio [OR] 2.1, 95% confidence interval [CI] 1.0 to 4.4), history of heart failure (OR 2.6, 95% CI 1.3 to 5.2), abnormal sestamibi scan results (OR 10.0, 95% CI 2.3 to 43.0) and reversible perfusion defects (OR 3.2, 95% CI 1.6 to 6.4) had independent predictive value. Patients without perfusion defects, with fixed defects alone, reversible defects alone and fixed plus reversible defects had annual hard cardiac event rates of 0.8%, 6.8%, 8.1% and 11.6%, respectively. Patients with increasing reversible defect scores had increasing annual event rates of 2.1%, 5.0%, 5.5%, 13.0% and 14.6%, respectively. CONCLUSIONS: Dobutamine-atropine stress Tc-99m sestamibi SPECT imaging provides excellent prognostic information. The single most important independent predictor for future hard cardiac events is an abnormal pattern, and a reversible defect provides additional, independent prognostic information. Moreover, the extent and severity of reversible defects are major determinants for prognosis.

Improvement of left ventricular ejection fraction, heart failure symptoms and prognosis after revascularization in patients with chronic coronary artery disease and viable myocardium detected by dobutamine stress echocardiography.

OBJECTIVES: This study was designed to address, in patients with severe ischemic left ventricular dysfunction, whether dobutamine stress echocardiography (DSE) can predict improvement of left ventricular ejection fraction (LVEF), functional status and long-term prognosis after revascularization. BACKGROUND: Dobutamine stress echocardiography can predict improvement of wall motion after revascularization. The relation between viability, improvement of function, improvement of heart failure symptoms and long-term prognosis has not been studied. METHODS: We studied 68 patients with DSE before revascularization; 62 patients underwent resting echocardiography/radionuclide ventriculography before and three months after revascularization. Long-term follow-up data (New York Heart Association [NYHA] functional class, Canadian Cardiovascular Society [CCS] classification and events) were acquired up to two years. RESULTS: Patients with > or =4 viable segments on DSE (group A, n = 22) improved in LVEF at three months (from 27+/-6% to 33+/-7%, p < 0.01), in NYHA functional class (from 3.2+/-0.7 to 1.6+/-0.5, p < 0.01) and in CCS classification (from 2.9+/-0.3 to 1.2+/-0.4, p < 0.01); in patients with <4 viable segments (group B, n = 40) LVEF and NYHA functional class did not improve, whereas CCS classification improved significantly (from 3.0+/-0.8 to 1.3+/-0.5, p < 0.01). A higher event rate was observed at long-term follow-up in group B versus group A (47% vs. 17%, p < 0.05). CONCLUSIONS: Patients with substantial viability on DSE demonstrated improvement in LVEF and NYHA functional class after revascularization; viability was also associated with a favorable prognosis after revascularization.

Biphasic response to dobutamine predicts improvement of global left ventricular function after surgical revascularization in patients with stable coronary artery disease: implications of time course of recovery on diagnostic accuracy.

OBJECTIVES: This study sought to evaluate the time course of improvement of left ventricular (LV) dysfunction in stable patients and its implications on the accuracy of dobutamine echocardiography for predicting improvement after surgical revascularization. BACKGROUND: Little is known about the optimal timing for evaluation of postrevascularization recovery of the contractile function of viable myocardium. METHODS: Sixty-one patients with chronic ischemic LV dysfunction scheduled for elective surgical revascularization were prospectively selected. They underwent dobutamine echocardiography (5 to 40 microg/kg body weight per min) and radionuclide ventriculography both preoperatively and at 3-month follow-up. At 14 months, another evaluation of LV function was obtained. To analyze echocardiograms, a 16-segment model and a five-point scoring system were used. Dyssynergic segments were considered likely to recover in the presence of a biphasic contractile response to dobutamine. Improvement of global function was defined as a > or =5% increase in LV ejection fraction (LVEF). RESULTS: Of the 61 patients, LVEF improved in 12 at 3 months and in 19 at late follow-up (from 32+/-8% to 42+/-9%, p < 0.0001). The frequency and time course of improvement of LVEF were similar in patients with mild and severe LV dysfunction. A biphasic response, identified in 186 of the 537 dyssynergic segments, was predictive of recovery in 63% at 3 months and in 75% at late follow-up. The positive predictive value was best in the most severe dyssynergic segments (90% vs. 67%). Other responses were highly predictive for nonrecovery (92%). The sensitivity and specificity for improvement of global function on a patient basis (> or =4 biphasic segments) were 89% and 81%, respectively, at late follow-up. CONCLUSIONS: Serial postoperative follow-up studies demonstrate incomplete recovery of contractile function at 3 months. The diagnostic accuracy of dobutamine echocardiography for predicting recovery is dependent on three factors: the combining of low and high dobutamine dosages, the severity of regional dyssynergy and the timing of evaluation.

Dobutamine-induced hypoperfusion without transient wall motion abnormalities: less severe ischemia or less severe stress?

OBJECTIVES: This study sought to compare the clinical characteristics, hemodynamic response and severity of ischemia in patients with coronary artery disease and reversible perfusion defects on dobutamine 2-methoxy isobutyl isonitrile (MIBI) single-photon emission computed tomography (SPECT) with or without transient wall motion abnormalities. BACKGROUND: The occurrence of reversible perfusion defects without concomitant wall motion abnormalities in patients with coronary artery disease was attributed to less severe ischemia. However, little data are available to support this observation. METHODS: Fifty-four consecutive patients with significant coronary artery disease and reversible perfusion defects on dobutamine (up to 40 micrograms/kg body weight per min) MIBI SPECT were studied (mean [+/- SD] age 59 +/- 11 years; 38 men, 16 women). All patients underwent simultaneous echocardiography. The myocardium was divided into six matched segments, and ischemic perfusion score was quantitatively derived in myocardial segments with reversible defects. RESULTS: New or worsening wall motion abnormalities occurred in 40 patients (74%) (group A) and were absent in 14 (26%) (group B). There was no significant difference between the two groups with respect to age, previous myocardial infarction, number of abnormal coronary arteries (1.8 +/- 0.8 vs. 1.6 +/- 0.9), number of reversible perfusion defects (1.6 +/- 0.9 vs. 1.8 +/- 0.7) or ischemic perfusion score (412 +/- 750 vs. 526 +/- 553). Patients in group A had a higher prevalence of male gender (80% vs. 43%, p < 0.01), higher peak systolic blood pressure (147 +/- 30 vs. 127 +/- 31 mm Hg, p < 0.05), higher peak rate-pressure product (19,632 +/- 4,081 vs. 16,939 +/- 4,344, p < 0.01) and a higher prevalence of angina (53% vs. 14%) and ST segment depression (55% vs. 14%) than group B (p < 0.05 for both). CONCLUSIONS: In patients with coronary artery disease and ischemia on dobutamine MIBI SPECT, the absence of transient wall motion abnormalities is associated with a similar extent and severity of reversible perfusion defects, a lower stress rate-pressure product and a higher prevalence of female gender than patients with transient wall motion abnormalities. Mechanically silent ischemia should not be regarded as a marker of less severe ischemia on myocardial perfusion scintigraphy.

Safety and feasibility of dobutamine-atropine stress echocardiography for the diagnosis of coronary artery disease in diabetic patients unable to perform an exercise stress test.

OBJECTIVE: Dobutamine stress testing is increasingly used for the diagnosis and functional evaluation of coronary artery disease. However, little is known about the safety and feasibility of this stress modality in diabetic patients. RESEARCH DESIGN AND METHODS: We studied the impact of diabetes on hemodynamic profile and on the safety and feasibility of dobutamine (up to 40 microg x kg(-1) x min(-1)) and atropine (up to 1 mg) stress echocardiography for the diagnosis of coronary artery disease in 1,446 consecutive patients (aged 60+/-12 years, 962 men) with limited exercise capacity and suspected myocardial ischemia. Of these, 184 patients were known to have IDDM or NIDDM. The test was considered feasible when 85% of the maximal heart rate and/or an ischemic end point (new or worsened wall motion abnormalities, ST segment depression, or angina) was achieved. RESULTS: No myocardial infarction or death occurred during the test. There was no significant difference between diabetic and nondiabetic patients with regard to heart rate increase during dobutamine stress echocardiography (58+/-25 vs. 61+/-24 beats/min), peak rate pressure product (18,400+/-3,135 vs. 18,048+/-4454), or the prevalence of hypotension (systolic blood pressure drop of >40 mmHg) (7 vs. 5%), ventricular tachycardia (5.4 vs. 4.5%), and supraventricular tachycardia (3 vs. 4%) during the test. Dobutamine stress echocardiography was feasible in 92% of the diabetic patients and in 90% of the nondiabetic patients. Coronary angiography was performed in 55 diabetic and 240 nondiabetic patients. Sensitivity, specificity, and accuracy of dobutamine stress echocardiography for the diagnosis of coronary artery disease in diabetic patients were 81, 85, and 82%. Those in nondiabetic patients were 74, 87, and 77%, respectively (NS). CONCLUSIONS: Dobutamine stress echocardiography is a feasible method for the diagnosis of coronary artery disease in patients with limited exercise capacity with a comparable safety, feasibility, and accuracy in diabetic and nondiabetic patients.

Safety and feasibility of dobutamine-atropine stress testing in hypertensive patients.

Dobutamine stress testing is increasingly used for the diagnosis and functional evaluation of coronary artery disease. The aim of this study was to assess the hemodynamic profile, safety, and feasibility of dobutamine stress testing in hypertensive patients. Dobutamine (up to 40 micrograms/kg per minute)-atropine (up to 1 mg) stress echocardiography was performed for the detection of myocardial ischemia in 1164 patients with limited exercise capacity (age, 60 +/- 12 years; 761 men); 446 patients were known to have hypertension. The test was considered feasible when 85% of the maximal heart rate and/or an ischemic end point (new or worsened wall motion abnormalities, ST segment depression, or angina) was achieved. No myocardial infarction or death occurred during the test. Dobutamine induced a significant increase of heart rate in patients with and without hypertension (59 +/- 25 and 63 +/- 23 beats per minute, respectively). Peak rate pressure product was similar in patients with and without hypertension (18,566 +/- 4584 and 18,230 +/- 4508). Hypotension (systolic pressure drop > 40 mm Hg) during the test was more frequent in hypertensive patients (7% versus 4% in normotensive, P < .05). Independent predictors of hypotension were baseline systolic pressure greater than 140 mm Hg (odds ratio, 6.9; 95% confidence interval, 3.4 to 14), older age (odds ratio, 1.04; 95% confidence interval, 1.01 to 1.07), and medication with calcium channel blockers (odds ratio, 1.8; 95% confidence interval, 1.1 to 3.5). The prevalence of ventricular tachycardia was similar (4.1%) in both groups. Episodes of 10 beats or more (0.06% of patients) were terminated promptly by intravenous metoprolol administration. Dobutamine stress testing was considered feasible in 91% of patients with and 92% of patients without hypertension. Dobutamine-atropine stress echocardiography is a safe and feasible method for the assessment of hypertensive patients referred for evaluation of myocardial ischemia. Despite the higher prevalence of dobutamine-induced hypotension in these patients, the feasibility of the test is comparable to that in individuals without hypertension.

Exercise echocardiography for the prognostic stratification of patients with low pretest probability of coronary artery disease.

PURPOSE: The aim of this study was to determine whether exercise echocardiography provides incremental data for risk stratification of patients with a low pretest probability of coronary artery disease. PATIENTS AND METHODS: The study included patients referred for exercise echocardiography whose probability of coronary artery disease was 25% or less. We calculated an exercise wall motion score index (on a 1-5 scale), an indicator of the extent and severity of exercise-induced abnormalities. The primary outcomes of the study were subsequent cardiac events (cardiac death and nonfatal myocardial infarction). RESULTS: We studied 571 men and 1047 women; their mean (+/- SD) age was 55 +/- 13 years. During a median follow-up of 3 years, there were 19 cardiac events (6 cardiac deaths and 13 nonfatal myocardial infarctions); an additional 37 patients underwent coronary revascularization. In a multivariate analysis of clinical, exercise electrocardiographic, and echocardiographic parameters, exercise wall motion score index (hazard ratio [HR] = 2.1 per 0.5 units; 95% confidence interval [CI]: 1.3 to 3.4), and age (HR = 2.0 per decade; 95% CI: 1.2-2.8) were independently associated with the risk of cardiac events. Although exercise echocardiographic variables contributed significantly (P = 0.01) to a model of the risk of adverse events, only 9 (47%) of the 19 patients with cardiac events were identified by an abnormal exercise echocardiogram. CONCLUSION: Among patients with low pretest probability of coronary artery disease by clinical criteria, exercise echocardiography identifies some, but not all, patients at risk of future events. Because of the low event rate, routine application of exercise echocardiography in a patient with a low pretest probability does not appear to be cost-effective and therefore cannot be recommended.

Thromboembolic complications after electrical cardioversion in patients with atrial flutter.

PURPOSE: To determine the incidence of thromboembolic complications after cardioversion in patients with atrial flutter. SUBJECTS AND METHODS: We reviewed 615 electrical cardioversions performed electively in 493 patients with atrial flutter. Embolic complications were evaluated during the 30 days after cardioversion. Follow-up data were obtained by follow-up visits and by contacting the treating physician. RESULTS: Anticoagulants had been administered in 415 cardioversions (67%). Cardioversion was successful in 570 procedures (93%). Three embolic events (in 3 patients) occurred in the 30 days after 550 successful cardioversions with completed follow-up (0.6% of successful procedures; 95% confidence interval, 0.1% to 1.6%). Two of the 3 patients had not been anticoagulated, whereas the third patient had subtherapeutic oral anticoagulation. No embolic event occurred in procedures performed with adequate anticoagulation. The incidence of embolism in patients regardless of subtherapeutic anticoagulation was 1% (3 of 303 successful cardioversions). CONCLUSIONS: We observed a low (0.6%) incidence of postcardioversion thromboembolic complications in patients with atrial flutter. Embolic events did not occur in patients with adequate anticoagulation.

Myocardial perfusion abnormalities in treated hypertensive patients without known coronary artery disease.

OBJECTIVE: Myocardial perfusion abnormalities may occur in hypertensive patients in absence of significant coronary artery disease. However, it is not well established whether hypertensive patients without known coronary artery disease have a higher prevalence or extent of myocardial perfusion abnormalities compared with normotensive patients with similar clinical features. DESIGN: This study compares the prevalence and extent of rest and stress-induced myocardial perfusion abnormalities in patients with and without hypertension. METHODS: Dobutamine (up to 40 microg/kg per min) stress technetium-99m myocardial perfusion SPECT imaging was performed for evaluation of myocardial ischaemia in 350 patients (mean age = 60+/-13 years, 146 men) without known coronary artery disease. One hundred and forty-eight patients were hypertensive. Rest SPECT images were acquired 24 h after the test Abnormal perfusion was defined as the presence of reversible or fixed perfusion defects. RESULTS: No significant difference was detected between patients with and without hypertension regarding gender, prevalence of symptoms, risk factors, pretest probability of coronary artery disease (52+/-28 versus 53+/-29%), peak rate pressure product (21040+/-4755 versus 20774+/-4865) or number of patients achieving the target heart rate during stress (85 versus 86%). Hypertensive patients were significantly older (62+/-11 versus 58+/-13 years, P = 0.005) and were receiving beta-blockers more frequently (34 versus 18%, P = 0.0001). The prevalence of myocardial perfusion abnormalities was similar in patients with and without hypertension (28 versus 31% in patients with low, 38 versus 33% in patients with intermediate and 60 versus 58% in patients with high pretest probability of coronary artery disease, respectively). No significant difference was detected between the two groups regarding stress perfusion defect score (1.45+/-2.5 versus 1.50+/-2.6) or rest score (0.72+/-1.8 versus 0.68+/-1.6). CONCLUSION: Treated hypertensive patients without known coronary artery disease have a similar prevalence and severity of myocardial perfusion abnormalities at rest and at dobutamine stress compared with normotensive patients with similar clinical characteristics.

Functional assessment of ALCAPA syndrome by dobutamine stress thallium-201 SPECT and echocardiography.

Exercise 201TI SPECT has been used as a useful method for the assessment of patients with anomalous left coronary artery communicating to the pulmonary artery (ALCAPA syndrome). In this study, we described an adult patient with this anomaly who was evaluated by dobutamine stress testing in conjunction with simultaneous 201Tl SPECT and echocardiography before and after surgery. A large perfusion defect in the anterior wall, septum and apex was detected on the preoperative stress scan with partial reversibility on reinjection scan. Worsening of wall motion abnormalities in the septum and anterior wall was detected by stress echocardiography. In the studies performed 3 mo and 1 yr after reimplantation of the left coronary artery in the aorta, a smaller fixed perfusion defect in the anterior wall and apex was detected without reversibility. No stress-induced wall motion abnormalities were detected. Despite the improvement of perfusion, there was no improvement of regional or global left ventricular function at rest. We report that both dobutamine 201Tl SPECT and echocardiography were useful for the detection of reversible ischemia and for the assessment of the surgical outcome of an adult patient with ALCAPA syndrome.

Relationship between preoperative viability and postoperative improvement in LVEF and heart failure symptoms.

UNLABELLED: The presence of myocardial viability is predictive of improvement in regional left ventricular (LV) function after revascularization. Studies on predicting improvement in global LV function are scarce, and the amount of viable myocardium needed for improvement in LV ejection fraction (LVEF) after revascularization is unknown. Moreover, whether the presence of viability is associated with relief of heart failure symptoms after revascularization is uncertain. Hence, the aims were to define the extent of viable myocardium needed for improvement in LVEF and to determine whether preoperative viability testing can predict improvement in heart failure symptoms. METHODS: Patients (n = 47) with ischemic cardiomyopathy (mean LVEF +/- SD, 30% +/- 6%) undergoing surgical revascularization were studied with 18F-FDG SPECT to assess viability. Regional and global function were measured before and 3-6 mo after revascularization. Heart failure symptoms were graded according to the New York Heart Association (NYHA) criteria, before and 3-6 mo after revascularization. RESULTS: The number of viable segments per patient was directly related to the improvement in LVEF after revascularization (r = 0.79, P < 0.01). Receiver operating characteristic curve analysis revealed that the cutoff level of four viable segments (representing 31% of the left ventricle) yielded the highest sensitivity and specificity (86% and 92%, respectively) for predicting improvement in LVEF. Furthermore, the presence of four or more viable segments predicted improvement in heart failure symptoms after revascularization, with positive and negative predictive values of 76% and 71%, respectively. CONCLUSION: The presence of substantial viability (four or more viable segments, 31% of the left ventricle) on FDG SPECT is predictive of improvement in LVEF and heart failure symptoms postoperatively.

Dobutamine thallium-201 SPECT imaging for assessment of peri-infarction and remote myocardial ischemia.

UNLABELLED: This study assessed the value of dobutamine 201Tl scintigraphy for detecting significant disease of infarct-related and remote coronary arteries in myocardial infarction patients. METHODS: Dobutamine (up to 40 micrograms/kg/min)/atropine (up to 1 mg) stress test in conjunction with stress-reinjection 200Tl SPECT was performed in 71 symptomatic patients with left ventricular dysfunction > 3 mo after myocardial infarction. Ischemia was defined as reversible perfusion defects. RESULTS: Significant coronary artery stenosis (> or = 50% luminal diameter stenosis) was detected in all patients. Sensitivity, specificity and accuracy of regional ischemia for the diagnosis of remote coronary artery stenosis were 74% (95% Cl 63-86), 80% (Cl 70-90) and 76% (Cl 65-87), respectively. Those for infarct-related artery stenosis were 71% (Cl 60-81), 83% (Cl 75-92) and 72% (Cl 61-82), respectively. Ischemic perfusion score was higher in patients with multiversus single-vessel disease (1056 +/- 1021 versus 423 +/- 633, p < 0.01). CONCLUSION: Dobutamine thallium scintigraphy is valuable for assessing the extent of coronary stenosis on the basis of reversible hypoperfusion in symptomatic patients late after myocardial infarction.

Safety of dobutamine-atropine stress myocardial perfusion scintigraphy.

UNLABELLED: Dobutamine stress testing is increasingly used for the diagnosis and functional evaluation of coronary artery disease. However, the relationship between myocardial perfusion abnormalities and complications of the test has not been studied. METHODS: We studied the hemodynamic profile, safety and feasibility of dobutamine (up to 40 microg/kg/min)-atropine (up to 1 mg) stress myocardial perfusion SPECT imaging (with 201TI, 99mTc-MIBI or tetrofosmin) in a consecutive series of 1076 patients (age = 59 +/- 11 yr, 50% with previous myocardial infarction) referred for evaluation of myocardial ischemia. RESULTS: No infarction or death occurred during the test. The test was considered feasible (achievement of 85% of the target heart rate or an ischemic endpoint) in 1005 patients (94%). Hypotension (systolic blood pressure drop > or = 40 mm Hg) occurred in 37 patients (3.4%). Independent predictors were higher baseline systolic blood pressure (p < 0.0001), number of ischemic segments (p < 0.05) and age (p < 0.05). Supraventricular tachyarrhythmias occurred in 48 patients (4.4%). Independent predictors were fixed perfusion defect (infarction) score (p < 0.005) and age (p < 0.05). Ventricular tachycardia occurred in 41 patients (3.8%). Independent predictors were infarction score (p < 0.01) and male gender (p < 0.05). All arrhythmias terminated spontaneously or after metoprolol administration. CONCLUSION: Dobutamine-atropine myocardial perfusion scintigraphy is a feasible method for the evaluation of coronary artery disease with a safety profile and feasibility comparable to those reported for dobutamine stress echocardiography. Patients with more severe fixed perfusion abnormalities are at a higher risk of developing tachyarrhythmias during the test.

Prediction of improvement of regional left ventricular function after revascularization using different perfusion-metabolism criteria.

UNLABELLED: Increased myocardial uptake of 18F-fluorodeoxyglucose (FDG) in regions with perfusion defects (perfusion-FDG mismatch) has been shown to predict functional recovery after revascularization; conversely, a concordant decrease in perfusion and FDG uptake (perfusion-FDG match) represents scar tissue (varying from subendocardial to transmural scar) that will not improve in contractile function after revascularization. Several recent studies have used a mild reduction in perfusion or FDG uptake (or both) as an indicator of viable tissue. To our knowledge, this criterion has not been validated against functional outcome after revascularization. This study aimed to compare the predictive value for functional recovery of these different perfusion-metabolism criteria. METHODS: Forty-two patients referred for revascularization were studied with early resting 201Tl SPECT (to evaluate perfusion) and FDG SPECT. Contractile function was evaluated before and 3-4 mo after revascularization using two-dimensional echocardiography. Angiography was not repeated. RESULTS: Two hundred six dysfunctional segments were identified; functional recovery occurred in 71 segments. The 206 dysfunctional segments were divided into five groups: group I, segments (n = 37) with normal perfusion; group II, segments (n = 69) with a mild reduction in perfusion (> or =60% of normal 201Tl uptake) without increased FDG uptake (mild match); group III, segments (n = 29) with a mild reduction in perfusion and increased FDG uptake (mild mismatch); group IV, segments (n = 46) with a more severe reduction in perfusion (<60% of normal 201Tl uptake) without increased FDG uptake (severe match); and group V, segments (n = 25) with a 201Tl activity < 60% and increased FDG uptake (severe mismatch). The mean wall motion score improved significantly in groups I, III and V but not in groups II and IV. Improvement of function was observed in 76% of group I segments, in 69% of group III segments and in 68% of group V segments. In contrast, only 13% of group II segments and 7% of group IV segments improved after revascularization. CONCLUSION: The results indicate that normal perfusion and mismatch patterns (either mild or severe) are predictive of functional recovery, whereas match patterns (either mild or severe) are predictive of absence of recovery. Match patterns are likely to represent different degrees of scar tissue, ranging from subendocardial to transmural scars. To identify segments with a high likelihood of improvement of function after revascularization, integration of information on perfusion and FDG uptake appears mandatory.

Five-year follow-up after percutaneous balloon mitral valvuloplasty in children and adolescents.

Balloon mitral valvuloplasty (BMV) is an effective intervention in patients with symptomatic mitral stenosis. However, the late results of BMV in children and adolescents have not been well studied. The aim of this study was to assess the late functional and morphologic results after BMV in children and adolescents. BMV was performed in 46 children and adolescents (mean age 15.5 +/- 3.2 years, range 7 to 19; 19 males) with rheumatic mitral stenosis. Serial clinical and echocardiographic evaluation was conducted to assess the long-term results of the procedure during a follow-up period of 66 +/- 6 months. The mitral valve score was 6 +/- 2/16. BMV was successful in 45 patients (98%). There was a significant increase of the mean mitral valve area index (MVAI) (0.65 +/- 0.14 vs 1.54 +/- 0.23 cm2/m2, p <0.001) and a significant reduction of the mean transmitral pressure gradient (16.1 +/- 2.9 vs 5.1 +/- 3.1 mm Hg, p <0.001) from pre- to post-BMV, respectively. There was no significant change of MVAI or the pressure gradient during the follow-up compared with immediately after BMV (1.51 +/- 0.31 cm2/m2 and 4.9 +/- 2.5 mm Hg, respectively). No deaths or mitral valve replacement occurred during the follow-up period. Restenosis (loss of >50% of the achieved increase in MVAI) occurred in 3 patients (6.5%). All other patients showed persistent improvement in their New York Heart Association class (< or = II). Thus, the event-free survival with good functional results was encountered in 42 patients (91%) at the end of the follow-up period. The left atrial diameter decreased from 4.6 +/- 0.9 before BMV to 3.7 +/- 0.6 cm at follow-up (p <0.05). It is concluded that BMV has excellent intermediate-term results in children and adolescents with a relatively low mitral valve score.