Exercise-induced ST-segment depression in patients without restenosis after coronary angioplasty. Relation to preprocedural impaired left ventricular function

BACKGROUND

ST-segment depression during exercise testing is frequently observed in the absence of restenosis after coronary angioplasty.

METHODS AND RESULTS

We studied the determinants of this phenomenon in 70 consecutive patients with unstable angina related to a single left anterior descending coronary artery lesion who had successful angioplasty without restenosis (< 50% stenosis by quantitative angiography). We compared preangioplasty clinical, angiographic, and hemodynamic variables in the group with positive (ExT Pos, n = 35; ST depression, 2.3 +/- 0.9 mm) and negative (ExT Neg, n = 35; ST depression, 0.3 +/- 0.5 mm) results on exercise testing at follow-up angiography. At this time, minimal lumen diameter (1.7 +/- 0.4 mm) and mean residual stenosis (34 +/- 11%) in the ExT Pos group were not significantly different from the values (1.9 +/- 0.5 mm, 38 +/- 10%) in the ExT Neg group. Before angioplasty, the ExT Pos group had a lower ejection fraction (63 +/- 8% versus 68 +/- 9%, P < .05), more marked anterior hypokinesis estimated by the extent of anterior wall contraction on quantitative ventriculography (P < .05), and a greater end-systolic volume (30 +/- 11 versus 25 +/- 9 mL/m2, P < .05) than the ExT Neg group. At follow-up angiography, regional anterior wall motion was normal in 68 patients (97%). Anterior hypokinesis before angioplasty was strongly associated (P < .01) with a positive exercise test at control (71% compared with 31% in patients with normal wall motion before angioplasty).

CONCLUSIONS

In the absence of significant epicardial stenosis after angioplasty, ST-segment depression is strongly associated with the presence of preprocedural regional ventricular dysfunction that has recovered at follow-up angiography.

[Predictive factors of primary success after coronary angioplasty. Qualitative and quantitative angiography of 3679 coronary stenosis before and after dilatation]

This study summarises the authors' experience of the prediction of primary success of coronary balloon angioplasty. A qualitative and quantitative angiographic study of 3679 coronary stenoses was undertaken before and after dilatation. Total occlusions before angioplasty and dilatations of saphenous vein bypass grafts were excluded. Two parameters were noteworthy: the occurrence of acute occlusion of the lesion during or immediately after angioplasty and the degree of residual stenosis as assessed by quantitative angiography. After multivariate analysis, 3 factors seemed strongly predictive of the risk of acute occlusion: the percentage stenosis before angioplasty, a left coronary artery stenosis and stenosis situated at the point of angulation of an artery. Quantitative angiographic studies identified 4 factors predictive of significant residual stenosis: the percentage stenosis before angioplasty, the irregularity of the contours of the lesion stenosis situated at the point of angulation of an artery and the presence of calcification. This study therefore shows at least two important discordances with the ACC/AHA morphological classification of coronary stenosis: firstly, excentricity would not seem to be a risk factor for primary failure of angioplasty and, secondly, excluding total occlusions, the percentage coronary stenosis before angioplasty as assessed by quantitative coronary angiography would seem to be the main predictive factor of both the risk of occlusion and the degree of residual stenosis.

Effect of balloon inflation in angiographically normal coronary segments during coronary angioscopy: a quantitative angiographic study

Visualization of coronary stenoses by coronary angioscopy is facilitated by inflating an occlusive cuff located near the distal end of the device to temporarily interrupt blood flow. In animal models, this procedure induces substantial endothelial denudation. Experimental studies show that endothelial denudation may lead to neointimal hyperplasia at the denuded site. This study was designed to determine whether angioscopy was associated with significant changes in lumen diameter at the site of cuff inflation. We studied 52 consecutive patients undergoing coronary angioscopy. We measured with use of quantitative edge-detection angiography [computer-assisted evaluation of stenosis and restenosis (CAESAR) system] the mean and minimal lumen diameters at the site of cuff inflation localized by filming the inflated cuff during angioscopy and at control non-instrumented segments on angiograms performed before angioscopy, after angioscopy, and at 6 months follow-up. Follow-up angiograms were performed in 80% of eligible patients. At follow-up, the mean (3.22 +/- 0.54 mm) and minimal (2.76 +/- 0.58 mm) diameters of the segment exposed to the inflated cuff were not significantly different from the equivalent values (3.22 +/- 0.58 and 2.75 +/- 0.61 mm) before angioscopy. No significant changes occurred in the mean or minimal diameters of the control segments over the same period. The late change (follow-up minus pre-angioscopy) in mean lumen diameter at the cuff inflation site (-0.005 +/- 0.18 mm) was not significantly different from that at the control site (0.004 +/- 0.20 mm).(ABSTRACT TRUNCATED AT 250 WORDS)

[Evaluation of the anesthetic risk in patients with coronary disease prior to non-cardiac surgery]

Evaluation of operative risk in coronary artery disease patients before non-cardiac surgery is a frequent problem concerning 100,000 patients each year in France. Perioperative cardiac morbidity is the first cause of death associated with non-cardiac surgery, with infarction rates of the order of 1 to 2% in coronary disease patients. These infarcts are followed by the death of the patient in 25 to 50% of cases. Evaluation of anesthetic risk is based upon three points: type of surgery, clinical findings and results of investigations. The risk is markedly increased in emergency surgery, and in thoracic, intraperitoneal and above all vascular surgery, in particular when clamping of the aorta is involved. From a clinical standpoint, only a history of infarction and signs of peripheral cardiac failure are independent predictive factors of postoperative complications. Other criteria, e.g. age, uncontrolled hypertension, diabetes and above all the severity of angina are also associated with the onset of perioperative-complications. This evaluation can be refined by electrocardiogram (Q wave, ST segment anomalies, ventricular hypertrophy and left bundle branch block) and chest X-ray. The usefulness and predictive value of exercise tests, when possible in a preoperative context, are particularly precious when the result is positive at low work-load. Many publications have studied the value of myocardial isotope scan, in particular before vascular surgery. They report the excellent negative predictive value (95 to 100%) of this investigation. Furthermore, the predictive value of isotope scan is all the greater when the clinical risk factors seen in the patients and the number of areas with ischemia are taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic significance of silent myocardial ischaemia during maximal exercise testing after a first acute myocardial infarction

Clinical, exercise, and angiographic variables, and long-term follow-up were compared in patients, who, during maximal Bruce exercise testing after a first acute myocardial infarction (AMI), had positive responses to exercise testing (n = 116, 38% of 303) with (n = 23, group I) or without (n = 93, group II) angina. Group I patients more often (52 vs 19%, P < 0.001) had a history of pre-infarction angina. Group II had a greater proportion (75 vs 52%, P < 0.05) of inferior wall AMI, whereas group I had a greater proportion (30 vs 19%, P < 0.01) of non-Q wave AMI. Total exercise duration was significantly (P < 0.01) longer in group II (7.6 +/- 3.2 vs 5.5 +/- 3.1 min). Maximal exercise heart rate (144 +/- 22 vs 133 +/- 21, beats.min-1 P < 0.05) was also higher in group II. A greater proportion of group II patients (37 vs 9%, P < 0.05) had single-vessel disease, whereas multivessel disease was more common (91 vs 63%, P < 0.03) in group I. Left ventricular function was similar in both groups. During follow-up (48 +/- 22 months) the incidence of cardiac death (group I, 3.3%, group II, 4.8%), of recurrent infarction (group I, 4.8%, group II 3.3%), and of revascularization procedures (group I, 28.5%, group II, 19.8%) were similar in both groups. Although asymptomatic exercise-induced ischaemia was associated with better exercise performance and less extensive coronary disease than symptomatic ischaemia, it had the same long-term prognostic implications.

[Should moderate coronary stenosis be dilated in patients with multi-vessel disease?]

This study evaluated the frequency of coronary angioplasty of non-significant (< 50%) stenoses during procedures of multiple revascularisation, and also determined the angiographic outcome of these dilatations at 6 months. All coronary lesions were assessed by quantitative angiography before and after angioplasty and at the 6 month control examination. In a population of 696 patients undergoing angioplasty of at least two coronary segments, 29 had a stenosis of < 50%. Angiographic control at 6 months was obtained in 26 of these patients (90%), corresponding to 61 coronary stenoses 29 of which were not significant (< 50%) (Group 1), and 32 of which were significant (Group 2) before angioplasty. By definition, before angioplasty, the lesions in Group 1 were less severe than in Group 2 (41.8 +/- 6.6% versus 65.9 +/- 9.6% respectively, p < 0.0001). After angioplasty, the degree of stenosis was comparable in the two groups (30.7 +/- 9.4% and 33 +/- 10.4%). At the 6 month control angiography, the percentage stenosis of the lesions in Group 2 (39.7 +/- 16%) remained significantly lower than before angioplasty (p < 0.0001). Six of these lesions (19%) developed restenosis. In Group 1, the percentage stenosis at control (39.5 +/- 18%) was comparable to that before angioplasty. Moreover, 5 lesions in Group 1 (17%) which were initially non-significant had > 50% stenosis at the 6 month control. These results show that dilatation of non-significant coronary stenosis during multiple revascularisation procedures is not common and should be avoided. Not only is there no benefit at 6 month control angiography but also the procedure may accelerate the evolution of the atherosclerosis.

Relative prognostic value of clinical, exercise, and angiographic data after a first myocardial infarction

BACKGROUND

Studies examining the relative value of clinical, exercise test, and angiographic data in the prediction of further clinical events after a first acute myocardial infarction (AMI) have produced conflicting results.

METHODS

We examined the relative value of clinical, exercise test, and angiographic data as predictors of death, recurrent infarction, and the subsequent development of angina or dyspnea in 303 consecutive patients who underwent exercise testing and coronary angiography within 2 months of an uncomplicated first acute myocardial infarction (AMI), and who were followed for 48 (+/- 22) months.

RESULTS

A combination of two clinical and two exercise variables correctly identified 79% of subsequent deaths. No variables had a predictive value for re-infarction. A combination of two exercise variables correctly identified 75% of patients who developed angina during follow up. A combination of two clinical variables and one exercise variable correctly identified 76% of patients who developed dyspnea during follow up.

CONCLUSIONS

Exercise testing provided useful prognostic information independent of clinical data. Combining clinical and exercise data identified a group of patients at low risk of future events. In this low-risk group of patients, the addition of angiographic data did not provide additional prognostic information.

Potassium channel activators in vasospastic angina

Activation of potassium channels induces relaxation of vascular smooth muscle, and experimental studies have demonstrated that potassium channel activators have potent coronary vasodilator properties. In humans, nicorandil, a potassium channel blocker, causes vasodilatation not only in angiographically normal segments but also at sites of dynamic coronary stenosis, where coronary spasm has been provoked by methylergometrine as well as at sites of spontaneous spasm. The efficacy of nicorandil in relieving ergometrine-induced spasm is comparable to that of nifedipine. Oral administration of nicorandil significantly reduces the frequency of anginal episodes in patients with vasospastic angina, and either as monotherapy, or in conjunction with other agents is a novel therapeutic option in patients with vasospastic angina.

Repeat percutaneous coronary angioplasty; clinical and angiographic follow-up in patients with stable or unstable angina pectoris

This study analyses the immediate outcome and the risk of recurrent restenosis in patients who, at the time of repeat coronary angioplasty for a first restenosis, had unstable (n = 50), 19%) or stable (n = 218, 81%) angina. Successful angioplasty was accomplished in 250 (93%) patients, 222 (89%) of whom had follow-up angiography. Mean time from initial to repeat angioplasty was shorter (P = 0.0002) and angiographic evidence of thrombus was commoner (P = 0.0001) in the unstable group. Major complications (coronary artery bypass grafting or myocardial infarction) were more frequent (P < 0.01) in the unstable group (6% vs 0.5%); no procedure-related deaths occurred. The angiographic rate of restenosis was significantly higher in the unstable group (61% vs 43%, P < 0.05). Despite this high rate of recurrent restenosis, most of the patients in both groups were either asymptomatic or had atypical chest pain at follow-up. Repeat coronary angioplasty, in patients with unstable angina, has a high primary success rate but a higher risk of acute complications than in patients with stable angina. The angiographic rate of restenosis was significantly higher in unstable than in stable patients; however, the clinical status of most patients was improved at follow-up.

Clinical characteristics and angiographic follow-up of patients undergoing early or late repeat dilation for a first restenosis

OBJECTIVE

The aim of this study was to analyze the angiographic rate of recurrent restenosis in patients who underwent repeat coronary angioplasty for a first restenosis within 3 months or greater than 3 months after the first procedure.

BACKGROUND

Several studies that have examined risk factors for restenosis after coronary angioplasty have suggested that a short interval between a first angioplasty and a repeat procedure is associated with an increased risk for a second restenosis.

METHODS

Between January 1981 and December 1990, 423 patients underwent a repeat coronary angioplasty procedure because restenosis had occurred at the site of a successful first angioplasty procedure. The clinical characteristics, immediate outcome and angiographic rate of recurrent restenosis were compared in patients who underwent repeat dilation within 3 months (early redilation group, n = 77) or greater than 3 months (late redilation group, n = 346) after the first procedure.

RESULTS

The incidence of unstable angina at the time of the repeat procedure was significantly higher in the patients who underwent early redilation (42% vs. 8%, p = 0.0001). The procedural success rate (95%) and complication rate were similar in both groups. Follow-up angiography was performed in 86% of patients with an initially successful procedure. The incidence of restenosis was significantly higher in the group that underwent early redilation (56% vs. 37%, p = 0.007) and was similar in patients in this group who presented with stable (55%) or unstable (57%) angina.

CONCLUSIONS

Rapidly recurring coronary stenoses have an extremely high rate of restenosis when again treated by coronary angioplasty, irrespective of the clinical presentation at the time of repeat dilation. The outcome in patients with early restenosis who have stable angina might be improved by delaying the repeat procedure.

Prognostic value of changes in R-wave amplitude during exercise testing after a first acute myocardial infarction

To investigate the prognostic value of exercise-induced changes in R-wave amplitude and their relation to other exercise and angiographic variables, 303 consecutive patients who underwent maximal exercise testing and coronary angiography within 2 months of a first acute myocardial infarction were studied. R-wave amplitude at peak exercise increased or was unchanged in 159 patients (57.4%) and decreased in 118 (42.6%). Increased R-wave amplitude was significantly related to underlying 3-vessel disease (p = 0.0001), the extent of ST-segment depression on exercise (p = 0.0001), and the time to 1 mm ST depression (p less than 0.05). Follow-up information was available in 285 patients (86.4%) at a mean of 4 +/- 1.8 years. Death from cardiac causes occurred in 25 patients (9%); 18 (6.5%) developed recurrent myocardial infarction, and 32 (11.6%) developed angina. Variables with a predictive value for cardiac death were maximal exercise heart rate (p = 0.0005), occurrence of exercise-related supraventricular arrythmia (p = 0.02), and number of diseased vessels (p = 0.02). R-wave changes had no predictive value. No variable had a predictive value for recurrent infarction. Maximal exercise heart rate (p = 0.02) and increased R-wave amplitude (p = 0.0001) were significantly related to the occurrence of angina at follow up. Exercise-related R-wave increases were associated with the presence of angina at follow-up, but had no predictive value for cardiac death or recurrent infarction; their association with subsequent angina appears to reflect an association with more severe underlying coronary disease.

Effect of ketanserin on proximal and distal coronary constrictor responses to intracoronary infusion of serotonin in patients with stable angina, patients with variant angina, and control patients

BACKGROUND

Serotonin, released by aggregating platelets, may contribute to or cause myocardial ischemia by constricting epicardial vessels. Experimental studies suggest that this constriction is mediated by two distinct serotonin receptor subtypes: 5-hydroxytryptamine1-like (S1-like) and 5-hydroxytryptamine2 (S2).

METHODS AND RESULTS

To determine the relative contribution of S1-like and S2 receptors to the vasoconstrictor effects of serotonin, we studied the effect of ketanserin (0.75 mg, intracoronary), a selective S2 receptor antagonist, on the constrictor response of human coronary vessels to intracoronary infusions of serotonin. In control patients (n = 7), serotonin (10(-4) mol/l) caused significant (p less than 0.05) constriction only in distal segments, which was significantly (p less than 0.05) inhibited by ketanserin. In stable angina patients (n = 8), serotonin (10(-4) mol/l) caused significant constriction in proximal (p less than 0.01) and distal (p less than 0.01) segments, which was significantly inhibited by ketanserin in proximal (p less than 0.05) but not distal (p = 0.30) segments. In patients with variant angina (n = 3), epicardial occlusion at the site of preexisting stenoses in proximal locations occurred at infused concentrations of 10(-6) (one patient) or 10(-5) (two patients) mol/l. The infusion of the same concentration of serotonin after ketanserin again caused epicardial occlusion.

CONCLUSIONS

Our results suggest that functionally important S1-like receptors that mediate vasoconstriction exist in the epicardial vessels of patients with stable or variant angina. Their activation, either at hyperreactive sites in patients with variant angina or in the distal epicardial vessels of patients with chronic stable angina, may contribute to or cause myocardial ischemia when serotonin is released after the intracoronary activation of platelets.

Effect of intracoronary serotonin on coronary vessels in patients with stable angina and patients with variant angina

BACKGROUND

Serotonin, a major product of platelet activation, has potent vasoactive effects in animal models, but its role in human coronary artery disease remains largely speculative.

METHODS

Using quantitative coronary angiography, we compared the effects of the intracoronary infusion of graded concentrations of serotonin (10(-7) to 10(-4) mol per liter) on coronary vessels in two groups of patients with different clinical presentations of coronary disease (nine with stable angina and five with variant angina), with the effects in a control group of eight subjects with normal vessels on angiography.

RESULTS

Normal coronary vessels had a biphasic response to intracoronary serotonin: dilation at concentrations up to 10(-5) mol per liter, but constriction at 10(-4) mol per liter. Vessels in patients with stable angina constricted at all concentrations, with mean (+/- SEM) maximal decreases in diameter of 23.9 +/- 3.6, 33.1 +/- 3.9, and 41.7 +/- 3.1 percent from base line in proximal, middle, and distal segments at a serotonin concentration of 10(-4) mol per liter. Smooth segments constricted more than irregular segments (42.0 +/- 4.6 vs. 21.1 +/- 1.6 percent). Four patients with stable angina had a marked reduction in collateral filling. All the patients with stable angina had angina during the intracoronary infusion of serotonin, and electrocardiographic changes were noted in six. All the patients with variant angina had angina, electrocardiographic changes, and localized occlusive epicardial coronary-artery spasm at concentrations of 10(-6) (n = 2) or 10(-5) (n = 3) mol per liter.

CONCLUSIONS

Patients with stable coronary disease do not have the normal vasodilator response to intracoronary serotonin, but rather have progressive constriction, which is particularly intense in small distal and collateral vessels. Patients with variant angina have occlusive coronary-artery spasm at a dose that dilates normal vessels and causes only slight constriction in vessels from patients with stable angina. These findings suggest that serotonin, released after the intracoronary activation of platelets, may contribute to or cause myocardial ischemia in patients with coronary artery disease.