Increased echodensity of transiently asynergic myocardium in humans: a novel echocardiographic sign of myocardial ischemia.

OBJECTIVES: This study was conducted to establish whether changes in myocardial texture can be observed in humans by transthoracic echocardiography during ischemic episodes of different severity and duration induced by various pathogenetic mechanisms. BACKGROUND: Increased echo-reflectivity of ischemic myocardium has been detected in experimental animals by epicardial echocardiography and by backscatter evaluation. METHODS: Transthoracic two-dimensional echocardiographic monitoring with a commercially available electronic sector scanner (2.25- or 3.5-MHz transducer) was performed during 35 episodes of transient myocardial ischemia induced by ergonovine in patients with vasospastic angina (n = 9), by dipyridamole in patients with angiographically assessed coronary artery disease (n = 11) and by balloon occlusion during coronary angioplasty (n = 15). Quantitative texture analysis of gray levels was performed off-line on digitized images during rest conditions, ischemia and the recovery phase in regions showing normal contraction at rest, obvious dyssynergy during ischemia and normal contraction in the recovery phase. In each condition, a control region with normal contraction throughout the study was also evaluated. RESULTS: Chest pain occurred in 23 of the 35 episodes; electrocardiographic (ECG) changes were present in 26 episodes, and consisted of ST segment elevation in 13, ST segment depression in 10 and pseudonormalization of a basally negative T wave in 3. The duration of ischemic episodes was 67 +/- 53 s by symptomatic criteria and 91 +/- 52 s by ECG criteria. The risk region showed an increased end-diastolic mean gray level amplitude in a.u. (arbitrary units) during ischemia (57 +/- 19) compared with rest (38 +/- 15) and recovery (38 +/- 18, p < 0.01). No significant changes were detected in the control region (rest 36 +/- 16 vs. ischemia 34 +/- 18 vs. recovery 31 +/- 13, p = NS). The percent increase in mean gray level was similar in the various types of stress employed (ergonovine, dipyridamole or angioplasty) and was not significantly correlated with either the duration of ST segment shift (r = 0.05, p = NS) or the severity of dyssynergy evaluated semiquantitatively by means of the wall motion score (r = 0.28, p = NS). In the 15 balloon occlusions performed in six patients during coronary angioplasty, the increased echoreflectivity of the risk zone was already evident during echocardiographic sampling performed after 10 +/- 4 s of occlusion (rest 35 +/- 9 vs. 53 +/- 10 a.u., p < 0.01) when no dyssynergy could be detected by quantitative wall motion analysis (percent area change by fixed center of mass reference system 31 +/- 10% at rest vs. 32 +/- 11% after 10 s of occlusion, p = NS). CONCLUSIONS: Transient short-lasting myocardial ischemia is associated with an abrupt increase in myocardial echodensity detectable by videodensitometric analysis applied to standard transthoracic echocardiographic images and is largely independent of the underlying pathogenetic mechanism (reduced blood supply or flow maldistribution with coronary stenosis). During controlled coronary occlusion, increased echodensity precedes the onset of regional dyssynergy.

Which variable of stenosis severity best describes the significance of an isolated left anterior descending coronary artery lesion? Correlation between quantitative coronary angiography, intracoronary Doppler measurements and high dose dipyridamole echocardiography.

OBJECTIVES: This study sought to investigate the angiographic or intracoronary Doppler variables of stenosis severity that best correlate with the results of dipyridamole echocardiography. BACKGROUND: Quantitative coronary angiography and intracoronary Doppler flow velocity assessments are the commonly used techniques for the objective identification of significant coronary artery stenosis. METHODS: Thirty patients with an isolated lesion of the left anterior descending coronary artery (LAD) were studied by means of on-line quantitative coronary arteriography, intracoronary Doppler flow velocity measurements and dipyridamole echocardiography 6 months after percutaneous transluminal coronary angioplasty. The quantitative arteriographic analyses were performed on-line; post-stenotic Doppler flow velocities were measured at baseline and after adenosine infusion. Angiographic and Doppler measurements were compared with the corresponding dipyridamole echocardiographic data and analyzed by discriminant analysis. RESULTS: The dipyridamole echocardiographic response was positive in 11 patients (37%). The best cutoff values for predicting an abnormal echocardiographic response were 1) stenotic flow reserve of 2.8 (p = 0.0001); 2) 59% diameter stenosis (p = 0.0001); 3) minimal lumen diameter of 1.35 mm (p = 0.001); 4) coronary flow reserve of 2.0 (p = 0.0002); and 5) maximal peak velocity of 60 cm/s during hyperemia (p = 0.04). Multivariate analysis identified stenotic flow reserve as the only independent predictor of ischemia during dipyridamole echocardiography. CONCLUSIONS: Stenotic flow reserve is the variable that best describes the functional significance of an isolated LAD lesion, and a value of 2.8 is the best predictor of a positive dipyridamole echocardiographic response. Furthermore, angiographic variables of stenosis severity relate to echocardiographic test results better than intracoronary Doppler variables.

Stent implantation versus balloon angioplasty in chronic coronary occlusions: results from the GISSOC trial. Gruppo Italiano di Studio sullo Stent nelle Occlusioni Coronariche.

OBJECTIVES: In this multicenter, randomized trial we evaluated whether stent implantation after successful recanalization of a chronic coronary occlusion reduced the incidence of restenosis. BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) in chronic total occlusions is associated with a higher rate of angiographic restenosis and reocclusion than PTCA in subtotal stenoses. Preliminary reports have suggested a decreased restenosis rate after stent implantation in coronary total occlusions. METHODS: We randomly assigned 110 patients with recanalized total occlusion to Palmaz-Schatz stent implantation, followed by 1 month of anticoagulant therapy versus no other treatment. The primary end point was the minimal lumen diameter (MLD) of the treated segment at follow-up, as determined by quantitative angiography at a core laboratory. RESULTS: Repeat coronary angiography was performed 9 months after the procedure in 88% of patients. The MLD (mean +/- SD) at follow-up was 1.74 +/- 0.88 mm in patients assigned to stent implantation and 0.85 +/- .75 mm in patients assigned to PTCA (p < 0.001). Stent implantation was associated with a lower incidence of restenosis (defined as diameter stenosis > or =50% at follow-up) (32% vs. 68%, p < 0.001) and reocclusion (8% vs. 34%, p = 0.003) than balloon PTCA. Likewise, stent-treated patients had less recurrent ischemia (14% vs. 46%, p = 0.002) and target lesion revascularization (5.3% vs. 22%, p = 0.038), but experienced a longer hospital stay. CONCLUSIONS: Palmaz-Schatz stent implantation after successful balloon PTCA of chronic total occlusions improves the midterm angiographic and clinical outcome and could be the preferred treatment option in selected patients with occluded vessels.

Prognostic significance of early ischemia after acute myocardial infarction in low-risk patients. IRES (Ischemia Residua) Study Group.

Early postinfarction angina is generally believed to imply an unfavorable prognosis. However, most of the published information devices from data collected in the prethrombolytic era, with widely differing populations and definitions of early angina, and very little data pertinent to low-risk patients are available. This collaborative study prospectively assessed the incidence of early recurrent ischemia after thrombolysis, as well as its prognostic significance, in 453 consecutive patients aged < or = 70 years with an uncomplicated course in the first 24 hours of a first myocardial infarction participating in the second Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-2) trial. Early recurrent ischemia (spontaneous, transient ST depression or elevation of > 1 mm and/or T-wave inversion), assessed in the coronary care unit with continuous clinical and electrocardiographic monitoring, was documented in 35 of 453 patients (8%) and was unrelated to sex, age, electrocardiographic location, Q-wave or non-Q-wave infarction, thrombolytic agent and time to its administration. In-hospital cardiac events (7 deaths, 19 nonfatal reinfarctions and 8 urgent revascularizations) occurred in 15 of 35 patients (43%) with versus 19 of 418 without (4.5%) recurrent ischemia (p < 0.001). At the 6-month follow-up of 352 medically treated patients who did not have in-hospital events, the incidence of death, reinfarction and recurrent angina was comparable between patients with (2 of 18, 11%) and without (62 of 334, 19%) early ischemia (p = NS). With use of stepwise multivariate analysis, early ischemia was the only significant predictor of in-hospital cardiac events (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of usefulness of high-dose dipyridamole echocardiography and exercise electrocardiography for detection of asymptomatic restenosis after coronary angioplasty.

The present study compares the relative usefulness of the maximal treadmill exercise electrocardiography test with the high-dose dipyridamole echocardiography test (echocardiographic monitoring during dipyridamole infusion up to 0.84 mg/kg in 10 minutes) in detecting severe restenosis or coronary artery disease progression (greater than 70% stenosis) in asymptomatic patients 12 months after a primary successful coronary angioplasty. Criteria of positivity were: for the exercise electrocardiography test, an ST-segment shift greater than or equal to 0.1 mV from baseline, 0.08 second from the J point; for the dipyridamole echocardiography test, a transient dyssynergy of contraction, absent or of a lesser degree than that in the baseline examination. The exercise electrocardiography and dipyridamole echocardiography tests revealed a similar feasibility (91 vs 87%, difference not significant). Both tests could be performed in 75 patients. For detection of restenosis or disease progression, or both, the exercise electrocardiography test revealed a sensitivity similar to the dipyridamole echocardiography test (71 vs 71%, difference not significant), but a lower specificity (61 vs 90%). It is concluded that the high-dose dipyridamole echocardiography test is equally feasible but more accurate than the exercise electrocardiography test for noninvasive detection of severe asymptomatic restenosis or disease progression at 1 year after successful coronary angioplasty.

Exercise thallium scintigraphy versus high-dose dipyridamole echocardiography testing for detection of asymptomatic restenosis in patients with positive exercise tests after coronary angioplasty.

The usefulness of high-dose (< or = 0.84 mg/kg over 10 minutes) dipyridamole echocardiography testing was compared with that of exercise thallium-201 scintigraphy in detecting restenosis (> 70% lumen reduction) in 50 asymptomatic patients with ST-segment depression during maximal exercise testing 3 months after successful coronary angioplasty. Dipyridamole echocardiography testing and exercise thallium scintigraphy showed a similar sensitivity (75 vs 83%; p = NS) and specificity (90 vs 84%; p = NS) for the detection of restenoses, which occurred in 12 patients. It is concluded that dipyridamole echocardiography testing is as accurate as exercise thallium testing for the noninvasive detection of severe restenosis in patients with exercise-induced asymptomatic ST-segment depression after successful angioplasty. Furthermore, the site, extent and severity of the thallium perfusion defects during exercise are correlated to those of the dyssynergy during dipyridamole echocardiography.

Absence of correlation between coronary thrombosis and postatherectomy restenosis.

This study endeavored to assess whether thrombus in directional coronary atherectomy was correlated with later subsequent restenosis. We concluded that the presence of thrombus in native plaque is not correlated with the occurrence of postatherectomy restenosis.

Comparison of coronary lesions obtained by directional coronary atherectomy in unstable angina, stable angina, and restenosis after either atherectomy or angioplasty.

The present study investigated the incidence of the histopathologic lesions and of growth factor expression in a consecutive series of directional coronary atherectomy (DCA) samples from 40 unstable angina pectoris patients without prior acute myocardial infarction and compared the findings with those obtained in DCA samples from 18 patients with stable angina without previous infarction and 18 patients with restenosis. We investigated coronary thrombosis, neointimal hyperplasia, and inflammation. For unstable angina, we correlated the angiographic Ambrose plaque subtypes with the histopathologic findings. The immunophenotype of plaque cells and the growth factor expression were assessed with specific antibodies for cell characterization and for the expression of basic fibroblast and platelet-derived AA and AB growth factors and receptors. The incidence of coronary thrombosis was 35% in patients with unstable angina, 17% in those with stable angina, and 11% in patients with restenosis. Neointimal hyperplasia was found in 38% of unstable angina cases, in 17% of stable angina cases, and in 83% of restenosis cases. Inflammation without thrombus or accelerated progression occurred in 20% of unstable angina and 6% of stable angina samples. In 52% of unstable angina cases, inflammation coexisted with thrombosis and/or neointimal hyperplasia. In the unstable angina group, 71% of the plaques with thrombus had a corresponding angiographic pattern of complicated lesions. The growth factor expression, reported as percentage of cells immunostaining with different growth factor antibodies, was highest in restenosis, followed by unstable angina and stable angina lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

[Transluminal coronary angioplasty. Technic and immediate results]. / L'angioplastica coronarica transluminale. Tecnica e risultati immediati.

Controlled crushing of the intimal plaque and of the underlying vessel wall are the determinants of transluminal dilatation of coronary stenoses. The technique of angioplasty has been recently modified in many laboratories, by the use of new catheters and dilatation policies. Data from the NHLBl Registry indicate a 59% primary success rate, being 29% and 12% respectively the failures due either to inability to cross or to dilate the stenosis. A retrospective analysis of successful procedures has highlighted factors that positively affect the results: recent onset of the angina, lack of calcifications, iterative ballooning at high pressures and the experience of the angiographer. Main complications were angina becoming unstable (5.7%) and acute coronary occlusion (4.4%); an emergency bypass operation had to be done in 6.3% of the cases, whereas myocardial infarctions scored 4.4% and hospital deaths less than 1%. Preliminary results of Centro De Gasperis concern 18 attempts to dilate LAD stenoses: primary success rate was 44% with a failure rate of 39% and 17% regarding inability to cross or only to dilate stenosis, respectively. The above results are less favorable than those reported in NHLBl Registry and very much less than those reported by selected laboratories; they are however acceptable in view of the suboptimal characteristics of the materials used and the limited experience of the team.

[Surgical indications and results of myocardial revascularization in complications of PTCA]. / Indicazioni chirurgiche e risultati della rivascolarizzazione miocardica nelle complicanze della PTCA.

Acute coronary occlusion during PTCA represents a significant procedural complication occurring in approximately 4-5% of cases, most frequently because of coronary dissection, spasm, or thrombosis. In these cases the first step in the management of acute ischemia is 1) a brief evaluation of its hemodynamic consequences and 2) the assessment and treatment of its cause. Spasm and intracoronary thrombus formation are usually readily identifiable and treatable using intracoronary nitroglycerin and thrombolytic therapy. In our catheterization laboratory the current approach to occlusive coronary dissection is represented by the use of autoperfusion dilatation catheters and by stent application. The atherectomy devices and the laser "welding" of the dissected intimal segment represent other alternatives that are still under clinical evaluation in this particular setting. If coronary occlusion is refractory to these efforts and coronary blood flow is not reestablished rapidly, emergency coronary bypass surgery is required to salvage jeopardized myocardium. In this case myocardial ischemia may be lessened by the insertion of an intra-aortic balloon pump. In our experience, the incidence of death (4%) and myocardial infarction (37%) for emergency CABG after a failed angioplasty, is similar to that reported by other Authors. The duration of myocardial ischemia and the presence of cardiogenic shock before operation are the most important determinants of major complications such as death and acute myocardial infarction.

[Unstable angina: immediate and mid-term results]. / Angina instabile: risultati immediati e a medio termine.

Coronary angioplasty (PTCA) for unstable angina is a procedure having good anatomical and clinical success. Best immediate results are achieved after a clinical "cooling" of the unstable phase, by means of intravenous heparin and acetylsalicylic acid. Coronary thrombolysis has no role in improving results of PTCA in unstable angina. Incomplete revascularization is safe and clinically effective in the acute phase, and staged procedures are recommended if two or more vessels are to be treated. Restenosis rate seems to be higher in unstable patients, especially in those who are on refractory phase.

[The Italian Group for the Study of Streptokinase in Myocardial Infarct: Coronarographic and ventriculographic study]. / G.I.S.S.I.: Studio coronarografico e ventricolografico.

The effects of intravenous thrombolytic treatment on the reperfusion of infarct related coronary artery and left ventricular function were assessed in 251 pts. with first episode of myocardial infarction, enrolled in the G.I.S.S.I. trial, in which coronary angiography and left ventriculography have been performed within the second and third week from the onset of symptoms. A total of 251 pts. were randomized in two groups--133 treated with streptokinase (SK) and 118 controls. Among those treated with SK, in 71 (57.9%) the treatment was started within 3 hours and in 56 (42.1%) after 3 hours from the onset of symptoms. The infarct related vessel was occluded in 43 (32.3%) patients treated and in 60 (50.9%) controls (p less than 0.01). No significant difference was found in the left ventricular ejection fraction among the treated patients and controls while a significant difference resulted in the percentage of patients who had left ventricular ejection fraction greater than or equal to 50% in the group of patients with SK within 3 hours in comparison to controls. Left ventricular ejection fraction remained normal without any correlation with the type and time of the treatment, if the infarct related vessel resulted open at the coronary angiography. The study of the regional wall motion of left ventricle did not show any significant difference neither in the infarct size nor in the type and the time of treatment. In conclusion, the thrombolitic treatment with SK in acute myocardial infarction using the protocol adopted in the G.I.S.S.I. trial, obtains the reopening of infarct related vessel in an high percentage of patients; this event helps in great measure to conserve left ventricular function, especially in patients with anterior myocardial infarction if the treatment was started within the first 3 hours from the onset of symptoms.

Percutaneous transluminal coronary angioplasty. Critical assessment of preliminary results.

Since June 1981 until July 1983, 40 percutaneous transluminal coronary angioplasty procedures in 38 patients have been performed. Results in the whole series are as follows: stenosis crossed in 33 patients (83%); balloon inflation done in 31 (78%), not done in 2 due to clinical instability induced by crossing of the stenosis; successful dilatation obtained in 25 patients (63%); emergency bypass surgery in 6 patients (15%) with 2 perioperative myocardial infarctions; no deaths. The whole series can be subdivided in two groups by the following parameters: premedication by nitrates (A) or by verapamil (B); temporal concentration of the procedures: 1/month up to February 83 (A), 3.7/month thereafter (B). Results are different in the two groups: 21 attempts in 21 patients: stenosis crossed in 14 cases (67%), balloon inflated in 12 (57%), successful dilatation obtained in 8 patients (38%), emergency bypass in 5 patients (24%). 19 attempts in 17 patients (2 vessel angioplasty in 2 patients): stenosis crossed and balloon inflated in 19 (100%), successful dilatation in 17 cases (89%), uncomplicated emergency bypass in 1 patient (5%). On the basis of personal more recent results an optimistic attitude towards the percutaneous transluminal coronary angioplasty is justified.

[Aorto-coronary bypass. On 200 cases surgically treated (author's transl]. / Il bypass aorto-coronarico. Considerazioni su 202 casi operti

200 patients underwent bypass graft for treatment of severe coronary vessel disease. The bypass vein grafts were 316; single grafts in 100 cases, double in 85, triple in 14 and in 1 case a patient received 4 grafts. In 57 cases a previous coronary endarterectomy was performed. The flow in the graft at the end of the operation was more than 40 cc/min. in 80% of cases. 22 patients died. Postoperative myocardial infarction occurred in 14% of the patients. The mortality was higher in the preinfarction angina group, and less in the chronic angina group without concomitant surgery (7,2%) and is statistically in direct relation to the functional condition of the left ventricle (2,8% in patients with end diastolic left ventricular pressure less than 20 mmHg and without akinetic areas). Relief of angina was observed in 87% of the surviving patients. Postoperative coronarography, catheterism and left ventriculography was performed in 46 patients. Only 2 of the 15 cases with postoperative angina had the graft patent. Significant improvement of the left ventricular function with disappearence or regression of akinetic areas was observed in 9 patients. Our experience indicates that the value of this operation cannot be entirely known at the present time.