Effects of therapy with nifedipine GITS or atenolol on mental stress-induced ischemic left ventricular dysfunction.

OBJECTIVES: We sought to determine the effect of nifedipine gastrointestinal therapeutic system (GITS) or atenolol on ischemic left ventricular dysfunction induced by mental stress. BACKGROUND: The efficacy of conventional antianginal therapy in preventing myocardial ischemia induced by mental stress is unknown. METHODS: Nifedipine GITS, atenolol and placebo were administered to 15 subjects with stable angina in a double-blind crossover trial. Subjects underwent a series of mental stressors at the end of each treatment. Radionuclide ventriculography was performed at baseline and at peak mental stress. Other measured variables included time to ischemia on exercise treadmill testing, ischemia on 48-h ambulatory electrocardiogram (ECG) monitoring, and resting and mental stress-induced levels of plasma catecholamines, tissue plasminogen activator antigen, plasminogen activator inhibitor-1 and platelet aggregability. RESULTS: Mental stress resulted in a significant increase in plasma epinephrine and norepinephrine levels during each treatment phase. Atenolol therapy was associated with lower baseline and postmental stress rate-pressure product compared with nifedipine or placebo. Therapy with either nifedipine GITS or atenolol prevented the development of wall-motion abnormalities and the decline in regional ejection fraction (EF) in the segment with the largest deterioration in wall motion during placebo therapy. Both medications prevented the decrease in global EF in subjects who demonstrated at least a 5% fall in global EF on placebo therapy. No therapy exerted a statistically significant benefit on exercise performance or frequency of ischemia during ambulatory ECG monitoring. CONCLUSIONS: Both nifedipine GITS and atenolol are effective at preventing mental stress-induced wall-motion abnormalities, although the mechanisms may be different.

Gated SPECT with technetium-99m-sestamibi for assessment of myocardial perfusion abnormalities.

High counting statistics with 99mTc-sestamibi make gated SPECT imaging realistic. Information obtained with gated and nongated SPECT were compared in 83 subjects (20 normals, 63 patients) using a 1-day protocol (250 MBq [6 mCi] rest, 900 MBq [24 mCi] peak stress). Studies were acquired for eight frames/RR interval and formatted to a standard nongated study, a study consisting of diastolic (DIA) frames and dynamic functional studies. The right ventricle appeared more distinct in DIA than in nongated studies (p < 0.01). The left ventricular cavity was larger in DIA studies (p < 0.001), leading to more coronal slices with cavity (p < 0.001). A strong inverse relation between left ventricular cavity size in nongated studies and increase in cavity size and in number of coronal slices with cavity in DIA studies was found (r = -0.74 and -0.67, both p < 0.001). Severity (extent and degree) of perfusion abnormalities in rest and stress studies, assessed quantitatively in 50 patients (20 normals as reference), correlated highly in nongated and DIA studies (r = 0.98, p < 0.001). Severity of small and moderate sized perfusion defects showed a high degree of agreement in nongated and DIA studies, while severity of large defects was less pronounced in DIA studies (p < 0.05). In patients with subtle perfusion abnormalities, the results from DIA imaging agreed best with clinical data.

Significance of increased right ventricular uptake on 99mTc-sestamibi SPECT in patients with coronary artery disease.

UNLABELLED: The significance of increased right ventricular (RV) tracer uptake in patients with coronary artery disease (CAD) without pulmonary or valvular heart disease is unclear. METHODS: Forty consecutive patients with increased RV uptake on SPECT myocardial perfusion imaging and right heart catheterization within 4 wk were studied prospectively. Thirty-five individuals with very low likelihood of CAD served as controls. Rest and stress SPECT myocardial perfusion data were obtained using a standard 99mTc-sestamibi 1-d imaging protocol. A quick and simple RV-to-left ventricular (LV) myocardial uptake ratio was calculated from the maximum counts per pixel detected in the right and left ventricles using the reconstructed coronal slices. RV end-systolic pressure (RV-ESP), mean pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure were obtained by standard techniques. RESULTS: The RV/LV uptake ratio in the controls was 0.31+/-0.05. Thirty-six of the 40 (90%) CAD patients with increased RV tracer uptake had increased RV-ESP, and 39 (97.5%) had increased PAP. Highly significant positive correlations between the RV/LV uptake ratio and RV-ESP and PAP were found (r = 0.45, P = 0.003; and r = 0.52, P < 0.001, respectively). CONCLUSION: Increased RV uptake, assessed from standard myocardial perfusion studies, can identify RV pressure overload among patients with CAD. In the absence of pulmonary or valvular heart disease, increased RV uptake (i.e., RV pressure overload) indicates significant backward failure, a variable with known significant negative prognostic implications.

Abnormal heart rate recovery after exercise as a reflection of an abnormal chronotropic response.

Abnormal decline in heart rate (HR) after exercise has been linked to increased cardiac mortality. This study compares the decrease in HR in different patient types, elucidates the relation between the increase and decrease of HR with exercise, and studies the role of beta blockers on the recovery of HR after exercise. One hundred patients with coronary artery disease (CAD), 50 subjects with a very low likelihood of CAD (normals), and 21 postcardiac transplant (Tx) patients underwent Bruce protocols. Peak HR, percent of peak HR achieved, HR reserve percent, and decline in HR at 1, 3, 5, and 8 minutes were obtained for all groups and also for subgroups based on the use of beta blockers. HR recovery at 1, 3, 5, and 8 minutes differed significantly between patients with CAD, normals, and Tx patients. HR recovery at 1, 3, 5, and 8 minutes also differed significantly within the groups (normal and CAD) based on the use of beta blockers. There was highly significant correlation between decrease in HR and peak HR, percent peak HR and HR reserve percent in normal and CAD groups. After correction of the HR recovery for dependence on peak HR and HR reserve percent, the difference in HR recovery between normal and CAD groups was markedly reduced. The difference in the decrease of HR within each group (normal and CAD), based on the use of beta blockers or not, was also markedly reduced. beta blockers have a significant impact on the decrease in HR due to its effect on chronotropism. HR recovery rate is highly dependent on the chronotropic response. Hence, the main portion of the abnormality in HR recovery after exercise can be explained by chronotropic incompetence.

Frequency of pulmonary embolism in patients with low-probability lung scan and negative lower extremity venous ultrasound.

STUDY OBJECTIVES: To define the prevalence of pulmonary embolism (PE) in patients who are undergoing pulmonary arteriography because of a high clinical suspicion for PE but who have had a low-probability lung scan and a negative lower extremity venous ultrasound examination. DESIGN: A retrospective review of the medical records of 365 consecutive patients who underwent pulmonary arteriograms for suspected PE was undertaken. RESULTS: Of the 365 pulmonary arteriograms, 62 were performed in patients with suspected PEs despite a low-probability lung scan and a negative lower extremity venous ultrasound examination. In the latter group, five patients (8%; 95% confidence interval, 2.7% to 18%) had PEs revealed on the arteriogram. CONCLUSIONS: In patients whose presentation provokes a high clinical suspicion for PE despite having had a low-probability lung scan, a negative lower extremity venous ultrasound examination is insufficient to preclude proceeding to pulmonary angiography.

Transmyocardial laser revascularization: operative techniques and clinical results at two years.

OBJECTIVES: A new technique, transmyocardial laser revascularization, provides direct perfusion of ischemic myocardium via laser-created transmural channels. From 1993 to 1995, we have treated 20 patients (mean age 61 years, four women and 16 men) with transmyocardial laser revascularization. Preoperatively, the average angina class was 3.7. The patients were screened before the operation by a technetium sestamibi perfusion scan to identify the location and extent of their reversible ischemia. METHODS: Operative exposure is gained via a left anterior thoracotomy. With the use of a 850-watt carbon dioxide laser, an average of 21 +/- 4 channels were created in 22 minutes with a total operative time of less than 2 hours. RESULTS: The in-hospital mortality was two of 20 patients. Three additional patients died after discharge. After an accumulated 172 patient-months (mean follow-up 11 +/- 8 months, range 1 to 26 months), the mean angina class is I (p = 0.01). Postoperative sestamibi scans were obtained at 3, 6, and 12 months. Using the septum as a control and comparing the postoperative results with the preoperative baseline, we noted a significant improvement in perfusion particularly in the areas of reversible ischemia. CONCLUSION: These early results indicate that transmyocardial laser revascularization is a simple operative technique that may improve myocardial perfusion and provide angina relief for patients in whom standard methods of revascularization is contraindicated.

Transmyocardial laser revascularization: results of a multicenter trial with transmyocardial laser revascularization used as sole therapy for end-stage coronary artery disease.

BACKGROUND: Transmyocardial laser revascularization was used as the sole therapy for patients with ischemic heart disease not amenable to percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. This technique uses a carbon dioxide laser to create transmyocardial channels for direct perfusion of the ischemic heart. METHODS: Since 1992, 200 patients, at eight hospitals in the United States, have undergone transmyocardial laser revascularization. The patients have a combined 1560 months of follow-up for an average of 10 +/- 3 months per patient. Their age was 63 +/- 10 years and their ejection fraction was 47% +/- 12%. Eighty-two percent had at least one previous bypass graft operation and 38% had a prior angioplasty. Preoperatively, the patients underwent nuclear single photon emission computed tomography perfusion scans to identify the extent and severity of their ischemia. These scans were repeated at 3, 6, and 12 months. Angina class, admissions for angina, and medications were recorded. RESULTS: The perioperative mortality was 9%. Angina class decreased significantly from before treatment to 3, 6, and 12 months (p < 0.001). Likewise, there was a significant decrease in the number of perfusion defects in the treated left ventricular free wall. Concomitantly, there was a significant decrease in the number of admissions for angina in the year after the procedure when compared with the year before treatment (2.5 vs 0.5 admissions per patient-year). CONCLUSION: These combined results indicate that transmyocardial laser revascularization provides angina relief, decreases hospital admissions, and improves perfusion in patients with severe coronary artery disease.

Dependence of shunt on cardiac output in unilobar oleic acid edema. Distribution of ventilation and perfusion.

OBJECTIVE: In acute respiratory failure, increased cardiac output (Qt) increases shunt (Qs/Qt). We have tested if this is caused by: 1) a redistribution of blood flow towards edematous regions, or 2) a decrease of regional ventilation in the edematous region. DESIGN: Oleic acid edema was induced in the left lower lobe (LLL) of 11 pigs. Qt was varied with bleeding and infusion of blood and dextran. Blood flow to the LLL was measured at low and high Qt with electromagnetic low probes in 6 animals and with a gamma camera in 5. In the gamma camera pigs regional ventilation was also measured. MEASUREMENTS AND RESULTS: Qt was increased by 45% (electromagnetic flow probes) and 73% (gamma camera). Qs/Qt increased from 24.9-31.3% (p < 0.05) and from 17.6-28.8% (p < 0.001) respectively. No change in fractional perfusion of LLL could be seen, neither with flow probes nor with gamma camera. A decrease in ventilation of LLL, 2.6%, was observed when Qt was increased (p < 0.05). CONCLUSION: Theoretically a small decrease in ventilation can explain the increase in shunt, if regions with low ventilation/perfusion (VA/Q) ratio are transformed to shunt. This is, however, unlikely since earlier studies have shown that blood flow is distributed either to regions with normal VA/Q ratio or to shunt regions. We conclude that the cardiac output dependent shunt is not caused by redistribution of blood flow between lobes or by decreased ventilation in the edematous region. We cannot exclude that blood flow is redistributed within the edematous lobe.

Long-term follow-up of residual mediastinal-hilar Ga-67 uptake after treatment for Hodgkin's and non-Hodgkin's lymphomas: what degree of Ga-67 uptake is significant?

PURPOSE: Ga-67 planar and SPECT images of 85 patients after treatment for mediastinal-hilar (M-H) lymphoma were reviewed retrospectively. Forty-seven patients had Hodgkin's disease and 38 patients had non-Hodgkin's lymphoma. The entire period was 7 years after diagnosis. The main goal was visual assessment of the significance of mild (grades 1 or 2) Ga-67 uptake in the M-H area as compared with Ga-67 uptake in bone marrow. METHODS: Residual Ga-67 mediastinal uptake after a complete course of chemotherapy or other treatments was defined as normal (no residual) M-H uptake, borderline (M-H residual uptake with intensity less than that or equal to the sternum, spine, or both), and abnormal (M-H residual uptake with intensity greater than that of the sternum or spine). RESULTS: Among the 38 patients (45%) with no residual M-H uptake, four (one Hodgkin's disease and three non-Hodgkin's lymphoma) experienced recurrence: two in the mediastinum and two in the abdomen. Among the 45 patients (53%) with borderline M-H uptake, five experienced recurrence: two in the mediastinum and three in other sites. The two patients (2%) with abnormal (M-H) uptake never responded to treatment. No significant statistical difference in tumor recurrence was found between no residual and borderline uptake (P = 0.21). CONCLUSIONS: Visual assessment of M-H Ga-67 uptake (without quantification) could be useful to differentiate active residual tumor from nonactive residual uptake.

A new method for quantification of pulmonary thallium uptake in myocardial SPECT studies.

Quantified pulmonary thallium 201 (Tl) uptake was assessed in 32 normal subjects and 66 patients with suspected coronary artery disease (CAD) by a new method utilizing SPECT acquisition data. In 26 subjects pulmonary uptake was assessed with both SPECT and planar techniques. Pulmonary/myocardial (PM) ratios for the whole right lung (PM1) and for the upper left lung (PM2) were computed and compared with stress test, coronary angiography, radionuclide angiography (ERNA), and quantified Tl single photon emission computed tomography (SPECT) results. Excellent correlation between pulmonary uptake assessed by planar and SPECT technique was disclosed (r = 0.92). The PM ratios (PM1/PM2) sensitivity and specificity in patients with CAD were 88%/92% and 60%/70%, for predicting perfusion abnormalities 90%/87% and 88%/88%, and an inverse correlation to left ventricular ejection fraction (LVEF) was found (r = -0.40/r = -0.37, P less than 0.01). Significant correlations to coronary angiography findings (r = 0.54/r = 0.49, P less than 0.001) and to number of vessel territories with abnormal perfusion (r = 0.70/r = 0.69, P less than 0.001) were seen. Thus, pulmonary Tl uptake can be assessed in SPECT studies. The new method's discriminative ability seems higher than that of the standard planar techniques currently employed. Positive correlations to coronary angiography findings and even stronger ones to perfusion abnormalities were observed.

Pulmonary thallium uptake: correlation with systolic and diastolic left ventricular function at rest and during exercise.

Quantified pulmonary 201-thallium uptake, assessed as pulmonary/myocardial ratios (PM) and body surface area-corrected absolute pulmonary uptake (Pc), was determined from single photon emission computed tomography studies in 22 normal subjects and 46 consecutive patients with coronary artery disease (CAD). By means of equilibrium radionuclide angiography (ERNA), ejection fraction (EF), peak ejection rate (PER) in end-diastolic volume (EDV/sec) and peak filling rate (PFR) in EDV/sec and stroke volume (SV/sec) units, PFR/PER ratio, and time to peak filling rate (TPFR) in milliseconds were computed at rest and during exercise (n = 35). Left ventricular response to exercise was assessed as delta EF, relative delta EF, delta EDV, and delta ESV. In normal subjects the PM ratios showed significant inverse correlation with PER at rest and with EF, PER, and PFRedv during exercise. For the left ventricular response to exercise, delta ESV showed significant correlation with the PM ratios. The body surface area-corrected pulmonary uptake values showed no correlation with any of the variables. In patients with CAD the PM ratios and Pc uptake showed significant inverse correlation with EF, PER, PFRedv and to exercise EF, exercise PER, and exercise PFRedv. For the left ventricular response to exercise, delta EF showed significant inverse correlation with the PM ratios but not with the Pc uptake. Neither in normal subjects nor in patients with CAD did any of the independent diastolic variables show significant correlation with the PM ratios or Pc values. Thus pulmonary thallium uptake is correlated with systolic left ventricular function at rest and during exercise in normal subjects and in patients with CAD but not with diastolic function. In normal subjects delta ESV and in patients with CAD, delta EF showed correlation with pulmonary thallium uptake.

Spatial distribution and temporal changes of pulmonary thallium uptake in myocardial perfusion studies.

Spatial distribution and temporal changes in pulmonary thallium uptake were assessed in 24 normal subjects and 35 patients with coronary artery disease (CAD). In studies carried out directly after stress and 3 h later, pulmonary Tl uptake was assessed as body surface area corrected absolute pulmonary uptake in the upper, middle and lower right lung regions, and in the total right lung and upper left lung. Pulmonary/myocardial (PM) uptake ratios for these 5 regions were calculated as mean pulmonary/mean background-corrected myocardial uptake. Additionally, wash-out was assessed for each region and for the myocardium. In normal subjects, the initial pulmonary Tl uptake, the PM ratios and Tl wash-out were greater in the lower lung regions than in the upper. In the late studies, no significant differences in Tl content or PM ratios were found among the regions. In patients with CAD, initial pulmonary Tl uptake and PM ratios were greater in the lower than in the upper regions, and higher than for the normal subjects in all pulmonary regions (P less than 0.001). Tl wash-out was significantly higher in the low and middle regions versus the upper region (P less than 0.001) and higher in all regions than in normal subjects (P less than 0.001). In the late studies no significant differences in Tl content or PM ratios were found between any pulmonary regions. Pulmonary Tl content was, in all regions, higher in CAD than in normal subjects (P less than 0.01), as were the PM ratios (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Does iron deficiency in treated polycythemia vera affect whole blood viscosity?

The relation between whole blood viscosity and iron status was studied in 11 patients with polycythemia vera (PV) who were treated with venesection without iron supplementation. Six were already iron deficient at the start of the study, five were followed from normal iron status to deficiency. Iron status was investigated with serum ferritin, erythrocyte protoporphyrin, mean cell volume and mean cell hemoglobin. There was no correlation between whole blood viscosity at a fixed erythrocyte volume fraction of 44% and any of these variables. The mean whole blood viscosity during iron deficiency and during normal iron state did not differ. Even after several months of iron deficiency there was no increase in whole blood viscosity. It is concluded that iron deficiency in treated PV does not give increased whole blood viscosity.

Left ventricular aneurysmectomy in patients with poor left ventricular function.

Physical performance and left ventricular (LV) function in the resting state were assessed in 22 patients with postinfarction anterior-apical left ventricular aneurysm (LVA) and global ejection fraction less than or equal to 20% who subsequently underwent radical LVA resection. The basic findings in the 20 survivors of surgery were significant improvement of global systolic LV function and more or less complete recovery of regional ejection fraction in the predominantly viable low and high lateral LV wall. This improvement was evident in patients with concomitant bypass grafting as well as in those with isolated and ungraftable lesions of the left anterior descending (LAD) coronary artery. We conclude that postinfarction anterior-apical LVA in a poorly functioning LV is suitable for surgical treatment, which can be accomplished with acceptable risk. All graftable stenotic major coronary arteries should be bypassed, in addition to the LVA resection, but a minority of patients with isolated, ungraftable LAD disease are likely to benefit from aneurysmectomy alone.

Mucociliary transport with and without the use of a heat and moisture exchanger. An animal study.

The importance to mucociliary transport (MCT) and the condition of the mucus of using a heat and moisture exchanger (HME) was investigated. A high tracheotomy was performed on 10 young pigs. The animals were ventilated using a non-breathing system. In five animals an HME was used; the other five were connected directly to the ventilator circuit. After 6 h the trachea was inspected via a flexible bronchoscope. Mucociliary transport velocity was measured using Tc-99-marked macrospheres and a gamma camera. In the control group the tracheal mucus membrane was desiccated at half the distance from the tube tip to the bifurcation. In the HME group the entire trachea was well moistened, but two cases showed large amounts of abnormally thin and foamy secretion. Mucus quality differed significantly between the two groups. Maximum MCT velocities were 8.3 +/- 4.6 and 4.9 +/- 3.0 mm/min for the HME- and the control groups, respectively. The marker had moved 49 +/- 32 and 35 +/- 21 mm during 24 min. Neither of these differences was statistically significant. In the control group there was no transport over desiccated areas. We conclude: 1) the quality of tracheal secretion differed significantly between the two groups, and 2) a heat and moisture exchanger may retain too much water in the airway.

Revascularization of infarcted vs. viable myocardium. Effects on symptoms, physical performance and global/regional left ventricular function.

Symptoms, physical performance and global vs. regional left ventricular (LV) function were reviewed in 25 patients with postinfarction anterior-apical akinesia and minor dyskinesia who subsequently underwent revascularization of all graftable stenotic vessels. The observed postoperative improvement in functional NYHA capacity and physical performance was not related to significant change in any systolic or diastolic variable of global LV function. 'Nonspecific postoperative septal hypokinesia' developed in most cases. The regional ejection fraction showed slight (nonsignificant) mean increase in the infarcted apex and low anterior wall supplied by the left anterior descending artery, but marked increase in the noninfarcted lateral wall supplied by the left circumflex branch. Hearts with grafted left circumflex artery showed on average lower preoperative and postoperative ejection fraction in the lateral wall than did hearts without such grafting, but the rise in regional ejection fraction was significant only after left circumflex grafting. The clinical response to coronary artery surgery is attributed mainly to functional improvement of non-infarcted myocardium. Revascularization of viable myocardium occurs directly via bypass grafts, but collateral vessels may also contribute.

Revascularization of infarcted myocardium. Effect on myocardial perfusion assessed with quantified Tl-201 SPECT technique.

Myocardial perfusion was studied in 21 patients before and after revascularization of all graftable stenotic vessels following post-infarction anteroapical akinesia and minor dyskinesia. At preoperative and late postoperative evaluation, perfusion abnormalities in identified sectors were quantified with two methods, one (Q1) assessing the extent and the other (Q3) the severity of abnormal perfusion. The preoperative scores with both methods indicated permanent myocardial perfusion defects in all 21 patients and reversible defects, indicating myocardial ischemia, in 16 with Q1 and 14 with Q3. After bypass grafting there was overall reduction of myocardial perfusion defect and of abnormality scores: Notably, 13/21 patients (62%) had decreased permanent myocardial defect score, reflecting reactivation of 'hibernating myocardium'. The findings indicated that obstructed but graftable vessels supplying myocardium with loss of contractile function should be bypassed, since flow contribution to distant, viable myocardium is probable via preserved collateral circulation. This should be particularly relevant for the LAD, because of that artery's septal branches.

Intrinsic limitations to unilateral parathyroid exploration.

OBJECTIVE: To evaluate a method of limited parathyroid exploration for primary hyperparathyroidism. SUMMARY BACKGROUND DATA: Although preoperative localization of parathyroid adenomas has become sensitive enough for clinical practice, it has not achieved success as the basis for limited parathyroid exploration, because multiglandular disease is routinely underdiagnosed. The rapid intraoperative parathyroid hormone assay is sensitive for multiglandular disease, because hormone levels will not fall within 10 minutes of adenoma removal if additional abnormal tissue is present. A combination technique in which the exploration is limited according to the localization studies and the success is confirmed with the parathyroid hormone assay has promise for producing a high rate of curative limited parathyroid explorations. METHODS: Forty-eight consecutive patients with primary hyperparathyroidism and indications for surgery underwent preoperative localization. After tests, 45 patients underwent unilateral parathyroid exploration and confirmation of the success of unilateral exploration during surgery using the rapid parathyroid hormone assay. The intraoperative management of these patients and their follow-up to 3 months was recorded. RESULTS: Thirty-two of the 48 patients (67%) had successful unilateral exploration as gauged by a marked drop in parathyroid hormone levels during the procedure and by 3-month clinical follow-up. Of the 16 patients who ultimately underwent bilateral exploration, 7 had parathyroid hormone levels that did not fall after adenoma removal. Of these seven, five were found to have a second adenoma and two had slow metabolism of hormone with no additional abnormal tissue found. In 5 of the 16 patients, bilateral exploration was performed for erroneous localization. Four additional patients underwent bilateral exploration for improved exposure or negative results on localization tests. CONCLUSIONS: These results show that unilateral parathyroid exploration is limited by the intrinsic 15% rate of multiglandular primary hyperparathyroidism, combined with the imperfections of preoperative localizing techniques. Although an 85% rate of unilateral exploration can theoretically be obtained for unselected cases, the other vagaries of the technique make a 70% rate a more reasonable expectation.