Percutaneous transluminal coronary angioplasty in patients with variant angina

Prinzmetal's variant angina

Although the prevalence of variant angina pectoris is unknown, it appears to be substantially less common than typical, exertional angina and unstable angina at rest. The patient with variant angina typically complains of a pressure-like, squeezing retrosternal chest discomfort of several minutes duration. The diagnosis is secured by the occurrence of transient ST-segment elevation in association with chest pain, both of which resolve spontaneously or with nitroglycerin. After the diagnosis is made, the patient usually becomes symptom-free on calcium-channel blockers with or without long-acting nitrates. Although the long-term survival of these patients is excellent, an occasional individual with variant angina sustains a complication, most often myocardial infarction, a life-threatening arrhythmia, or sudden cardiac death.

Stent implantation in variant angina refractory to medical treatment

BACKGROUND

Vasospastic angina usually responds well to medical treatment.

HYPOTHESIS

The present study describes our experience in patients who received a coronary stent because of recurrent variant angina refractory to medical treatment and evaluates stent implantation as an alternative treatment.

MATERIALS AND METHODS

Between March 1998 and February 2005, recurrent variant angina was diagnosed in 22 patients admitted to our coronary care unit. Of these, five patients (22.7%), were refractory to pharmacologic treatment. Coronary angiography and coronary stents were indicated. Clinical follow-up was 29 +/- 6 months.

RESULTS

Stenting was performed during diagnostic coronary angiography in two patients. In the other three patients, the stent was implanted 24-48 h later. We observed coronary spasm recurrences proximal or distal to the stent in four patients-two during the stent implantation procedure and the other two in the coronary care unit within 48 h post angioplasty. Three patients where treated with additional stenting and the fourth patient improved with pharmacologic treatment. During follow-up three patients remained asymptomatic. The fourth patient had diffuse in-stent restenosis in the third month, and the fifth patient showed a de novo lesion in the treated segment 2 years later.

CONCLUSIONS

Stent implantation in patients with recurrent variant angina refractory to medical treatment may be an alternative treatment in carefully selected, clinically unstable patients. Spasm recurrences may occur in other segments of the treated artery, probably due to the diffuse nature of the disease. Immediate and continued surveillance is recommended because of the risk of adverse clinical events.

Correlation of angiographic morphology immediately after coronary balloon angioplasty with coronary vasomotion late after angioplasty

BACKGROUND

Various vasomotor responses to acetylcholine have been observed after coronary angioplasty. However, the relationship between the grade of vascular injury due to balloon angioplasty and vasomotor response to acetylcholine in the chronic stage is unknown. In this study we examined the correlation between the morphology immediately after coronary angioplasty and the vasomotor response to acetylcholine 1 year after angioplasty.

METHODS

Thirty nine patients with a total of 45 coronary lesions without restenosis 1 year after angioplasty were studied. The 45 lesions were divided into two groups according to the morphology immediately after angioplasty. Group A comprised smooth-walled dilation and smooth-walled dilation with intraluminal haziness which were considered to be related to injury limited to the intima or the surface of the media. Group B comprised intraluminal and extraluminal haziness and extraluminal type dissection which were considered to be related to extensive medial injury. In the 39 patients, acetylcholine provocation test was performed.

RESULTS

Transient total occlusion of angioplasty site was induced by acetylcholine in four lesions only in Group A. Percent change in coronary diameter after acetylcholine injection relative to that after injection of isosorbide dinitrate at the angioplasty site was larger in Group A than that of Group B.

CONCLUSION

In the chronic stage, vessels with minor vascular injury exhibited a large vasomotor response to acetylcholine; conversely, the response was low in vessels with severe vascular injury by angioplasty. These observations suggest that severe vascular injury by balloon angioplasty may control coronary vasomotion in the chronic stage.

Stenting for coronary artery spasm

We evaluated coronary stenting in nine patients with clinically severe, angiographically documented spasm refractory to aggressive pharmacologic management. No patient subsequently developed unstable ischemia requiring hospitalization as a consequence of recurrent spasm within the stent. Mechanisms of therapeutic failure included both persistent spasm and spasm in a different artery in one patient. Restenosis occurred in three patients who subsequently underwent repeat revascularization. In the rare, carefully selected patient, stents may represent an adjunct in the management of focal coronary artery spasm, although currently medical therapy remains the standard initial approach.

Limited role of coronary angioplasty and stenting in coronary spastic angina with organic stenosis

OBJECTIVES

We investigated the efficacy of percutaneous coronary intervention (PCI) in patients with coronary spastic angina (CSA) and severe organic stenosis.

BACKGROUND

Coronary spasm occurs at the site of organic stenosis in most patients with CSA and severe stenosis, whereas multivessel spasm occurs frequently in those with normal coronary arteries. The incidence of multivessel spasm and the efficacy of PCI in patients with CSA and severe stenosis have not been fully elucidated.

METHODS

Forty-five patients with CSA and severe stenosis underwent spasm provocative testing with intracoronary acetylcholine before and 7 +/- 3 months after PCI (20 patients had angioplasty and 25 patients had stenting), when all patients were free of restenosis.

RESULTS

Spasm was induced at the site of severe stenosis in 30 patients (66.7%) with (n = 12) or without (n = 18) spasm induced in another vessel. In the remaining 15 patients, spasm was induced at a different site in the stenotic vessel and/or in another vessel. Repeat provocative tests were performed in 43 of 45 patients. Although spasm was never induced at exactly the same site of the initial stenosis that had been dilated, spasm was induced at a different site in the dilated vessel and/or in another vessel, in 33 (76.7%) of 43 patients. Multivessel spasm occurred in 28 (62.2%) of 45 patients on one or both provocations.

CONCLUSIONS

Spasm was frequently induced at a site different from the initial stenosis, even in the absence of restenosis after PCI. Calcium antagonists should be continued in most patients with CSA who show no restenosis after PCI.

Comparative results of coronary intervention in patients with variant angina versus those with non-variant angina

Coronary angioplasty is reported to be feasible and safe in patients with coronary spasm and fixed stenosis. However, the long-term results are not positive. We compared the results of coronary angioplasty in 20 patients with variant angina versus 17 patients with non-variant angina among 231 consecutive patients with vasospastic angina. Coronary angioplasty was performed successfully in all 37 patients without any complications. Stenting for coronary dissection or recoil was performed in 8 patients, directional coronary atherectomy was selected for ostial lesion of left anterior descending coronary artery stenosis in 2 patients, and standard balloon angioplasty was performed in 27 patients. There were no clinical differences between the two groups. The restensois rate in patients with variant angina was similar to that in patients with non-variant angina (30% vs 29%, ns). There was no relationship between the provoked spasm and restenosis. During the follow-up period, no major complications were observed in patients with variant angina or those with non-variant angina. In conclusion, full medication with calcium channel antagonists and isosorbide dinitrate, and treatment by coronary angioplasty including the use of new devices, were useful treatments for patients with coronary vasospasm and significant organic stenosis. There was no difference concerning the results of coronary intervention between the patients with variant angina and those with non-variant angina.

Lack of compensatory enlargement at sites of coronary vasospasm: identification by ultrasound and successful treatment with stenting

The case of a young man with spontaneous vasospasm at two sites in his left anterior descending coronary artery is described. Intravascular ultrasound demonstrated mild eccentric atherosclerosis with smaller total artery cross-sectional area (defined as the external elastic membrane) compared with reference segments. Impaired compensatory enlargement (remodeling) in response to mild atherosclerosis may derive from one or more biologic mechanisms that are also responsible for vasospasm. This characteristic is easily identified by intravascular ultrasound. In this case, coronary stenting of the vasospastic sites led to excellent long-term control of symptoms more than 1 year after intervention.

Successful management of intractable coronary spasm with a coronary stent

Although the long-term survival of patients suffering from coronary spasm is usually excellent, serious complications can develop, such as disabling pain, myocardial infarction, ventricular tachyarrhythmias, atrioventricular block and sudden cardiac death. A 40-year-old man who had intractable chest pain from coronary artery spasm suffered ventricular fibrillation and an acute anterior myocardial infarction upon first admission. The patient underwent a coronary angiogram, which revealed a spontaneous focal spasm at the proximal left anterior descending coronary artery (LAD). He was treated by the combination of nitrate and calcium channel blocker, but continued to complain of severe chest pain despite intensive medical therapy and he had to be treated in the emergency room 5 times during an 8-month follow-up period. An ergonovine coronary angiogram was performed and an intracoronary ultrasound examination, which revealed a focal spasm at the same site of the proximal LAD with a small amount of localized eccentric atheromatous plaque. A coronary artery stent was placed in the proximal LAD and his symptoms resolved. A follow-up coronary angiogram was performed 3 years after stenting and the stent remained patent without any in-stent restenosis or spasm.

Stent placement for recurrent vasospastic angina resistant to medical treatment

The successful stent placement for treatment of recurrent vasospastic angina in a patient with nonstenotic coronary arteries is described. Use of the Palmaz-Schatz stent resulted in successful vasodilation that completely prevented anginal attacks. This procedure represents an alternative treatment for patients with vasospastic angina refractory to aggressive medical therapy.

Effect of low grade radiofrequency heating on arterial vasospasm in the porcine model

Nineteen pigs were studied in order to assess the effect of low grade, radiofrequency-powered, thermal balloon angioplasty on the vasoconstrictor response of peripheral arteries. A mechanical stimulus was used to induce vasospasm. Thermal angioplasty reduced the extent of inducible vasospasm from 79% to 6% compared to nonthermal control inflations, which reduced the vasoconstrictor response from 75% to 60% (P < 0.001). Histologic studies demonstrated that the extent of myocyte necrosis was significantly greater in the thermally treated arteries than in the control vessels (P < 0.01). Thermal balloon angioplasty at 60 degrees C significantly attenuates peripheral arterial vasospasm induced by mechanical trauma in the porcine model. This paralytic effect may be related to the loss of myocytes secondary to thermal necrosis.

Role of platelets in restenosis after percutaneous coronary revascularization

The role of platelets in the process of restenosis after percutaneous coronary intervention is not fully understood. After vascular injury there is extensive platelet activation, adhesion, aggregation and secretion. Through the liberation of growth factors, such as platelet-derived growth factor, and surface expression of cell adhesion molecules, such as the glycoprotein IIb/IIIa integrin, platelets appear to be a pivotal mediator of the vascular injury response. Experimental models have demonstrated that profound, prolonged thrombocytopenia, or blockade of the IIb/IIIa receptor, may reduce neointimal hyperplasia after arterial balloon injury. However, multiple clinical trials testing conventional or new platelet agents have not yielded any salutary effects. The recent finding that abciximab, a monoclonal antibody fragment directed against IIb/IIIa, reduced clinical restenosis after coronary angioplasty by 26% in patients raises questions about the mechanism of benefit. The alpha v beta 3 vitronectin receptor is responsible for binding endothelial cells to platelets, and it also has a key role in modulating smooth muscle cell migration. It is possible that the antibody fragment exerts its effect on restenosis by means of alpha v beta 3, because abciximab fully cross-reacts to this integrin owing to the shared beta 3 subunit. To date, the other platelet glycoprotein IIb/IIIa inhibitors, including Integrelin, Tirofiban, Lamifiban and Xemilofiban, are specific in binding to this particular integrin. Considerable further study is necessary to unravel the effects of platelets on the restenosis process.

Directional coronary atherectomy for coronary artery spasm refractory to medical therapy

A patient with severe medically refractory coronary artery spasm was treated successfully with coronary atherectomy of a mild (40%) left anterior descending artery stenosis. Before the procedure, the patient was dependent on intravenous nitroglycerin because of daily episodes of angina with ST-segment elevation despite receiving multiple combinations of antianginal therapies. Clinical response to coronary atherectomy was prompt and dramatic.

A rare indication for stenting: persistent coronary artery spasm

A 34-year-old man presenting with angina both at rest and on exertion was investigated. He developed severe ST segment elevation and a brief period of ventricular tachycardia during an exercise tolerance test. On coronary angiography, 60% fixed luminal narrowing was observed in the proximal left anterior descending coronary artery and a severe spasm developed at this site, leading to temporary total occlusion of the vessel. Successful coronary angioplasty (PTCA) was performed on this lesion, with a residual 15% narrowing. However, the patient had a recurrence of angina 3 weeks later, despite being administered high doses of nitrate and calcium antagonist. During control angiography, the lesion severity was unchanged, but spasm developed again following contrast injection. At this time, a Palmaz-Schatz stent was implanted. Calcium antagonist, nitrate, Ticlopidine and low molecular weight heparin therapy was started. There was no recurrence of symptoms during a 3-month follow-up. The exercise tolerance test, and myocardial perfusion scintigraphy findings were normal and the stent was patent without restenosis at the end of the 3-month follow-up. Intracoronary stent implantation for persistent coronary spasm refractory to conventional medical therapy can be considered a feasible and attractive treatment modality for the control of symptoms.

Inhibitory effects of heparin, aspirin and ketanserin on coronary artery vasoconstriction after arterial balloon injury in hypercholesterolemic miniature pigs

OBJECTIVES

The present study aimed to clarify the effects of heparin, aspirin and ketanserin on coronary artery vasoconstriction after arterial balloon injury.

BACKGROUND

The mechanisms of coronary artery vasoconstriction after coronary angioplasty are not well understood.

METHODS

After being fed a cholesterol-rich diet for 1 month, 71 Göttingen miniature pigs were randomly allotted to five groups: 16 pigs with no pretreatment (group A); 21 pigs pretreated with heparin, 3,000 U (group B); 13 pigs pretreated with aspirin, 50 mg/day orally for 2 days (group C); 11 pigs pretreated with ketanserin, 1 mg/kg body weight (group D); 10 pigs pretreated with aspirin, 50 mg/day for 2 days, heparin, 6,000 U and ketanserin, 1 mg/kg (group E). After this pretreatment, the left anterior descending or the left circumflex coronary artery, or both, was denuded by a 2F balloon catheter.

RESULTS

The coronary vasoconstriction at the injured sites reached a peak level 6 min after the arterial injury and subsided within 30 min. The coronary vasoconstriction at the injured site 6 min after arterial injury was 56 +/- 5% in group A, which was significantly greater than that in group B (28 +/- 6%, p < 0.01), group C (25 +/- 5%, p < 0.01), group D (26 +/- 7%, p < 0.01) or group E (24 +/- 5%, p < 0.01), whereas there was no significant difference in the coronary vasoconstriction among the latter four groups.

CONCLUSION

These results suggest that serotonin released from aggregating platelets plays a major part in the platelet-dependent coronary artery vasoconstriction after arterial injury.

Abnormal coronary vasoconstriction as a predictor of restenosis after successful coronary angioplasty in patients with unstable angina pectoris

BACKGROUND

High rates of restenosis after coronary angioplasty have been reported in patients with vasospastic angina. This study was designed to determine whether the occurrence of abnormal coronary vasoconstriction, detected by means of hyperventilation testing before angioplasty, influences the risk of restenosis after successful dilation.

METHODS

Hyperventilation testing was performed 0 to 4 days before coronary angioplasty in 106 consecutive patients with unstable angina and single-vessel coronary artery disease. Abnormal coronary vasoconstriction was considered present if hyperventilation-induced myocardial ischemia occurred during the recovery phase of the test. All patients had follow-up angiography 8 to 12 months after angioplasty.

RESULTS

Abnormal coronary vasoconstriction was observed in 48 patients (group 1), whereas 58 patients (group 2) had either a negative response throughout the test or a positive response only during the overbreathing phase of the hyperventilation test. Angioplasty was successful in 40 patients in group 1 and 51 in group 2. Restenosis was documented in 29 patients (73 percent) in group 1 and 13 (25 percent) in group 2 (relative risk of restenosis, 2.84; 95 percent confidence interval, 1.69 to 4.28; P less than 0.001). In a multivariate analysis, the following three characteristics were independently related to the risk of restenosis (in descending order of importance): ST-segment elevation during spontaneous ischemic attacks (P less than 0.001), hyperventilation-induced abnormal coronary vasoconstriction (P less than 0.001), and the presence of a lesion more than 10 mm long in the left anterior descending coronary artery (P less than 0.05).

CONCLUSIONS

In patients with unstable angina and single-vessel coronary artery disease who have been selected for coronary angioplasty, the presence of hyperventilation-induced abnormal coronary vasoconstriction identifies a subgroup at high risk for restenosis.

The influence of the presence of collaterals on restenoses after PTCA

To assess the influence of collaterals on the long-term follow-up after successful percutaneous transluminal coronary arteriography (PTCA), 120 consecutive patients were studied. Of these, 104 (87%) had an adequate reangiogram and were included. At the time of PTCA the collaterals were estimated by a scoring system. In addition, the coronary wedge pressure was measured in 49 patients six months after PTCA, a follow-up angiogram was performed, and the patients were split up into a group with restenoses (stenosis greater than 50%), 34 patients (32.7%); and a group without restenoses (stenosis less than 50%), 70 patients (67.3%). A total of 35 patients (30.7%) had collaterals. A comparison between both groups showed no significant differences in clinical parameters (age, angina duration, vessel involvement, lipids, blood sugar, and blood pressure), and stenoses-related parameters (degree of stenoses, eccentricity, balloon size, inflation pressure, dissection, gradient after dilatation, and residual stenoses). Patients with collaterals had a significantly higher incidence of restenoses than those without collaterals (45.7% vs. 26.1%, p less than 0.05). Patients with wedge pressure of less than 45 mmHg (n = 30) had a significantly lower restenosis rate (23.3%) than patients with a coronary wedge pressure of greater than 45 mmHg (n = 19) (restenosis rate 52.6%). It is concluded that the presence of collaterals indicates a high restenosis rate after PTCA within 6 months.

Patient-related variables and restenosis after percutaneous transluminal coronary angioplasty--a report from the M-HEART Group

As part of a randomized prospective study designed to investigate the restenosis process after percutaneous transluminal coronary angioplasty (PTCA), the relation between patient-related variables and restenosis rate was examined. A total of 722 patients had successful PTCA. Angiographic follow-up was scheduled for 6 +/- 2 months after the procedure and achieved in 510 patients (71%), yielding 598 lesions for analysis. The overall restenosis rate was 40%. The rate was higher in patients undergoing early restudy for a clinical event than in those undergoing routinely scheduled follow-up restudy (71 vs 22%, p less than 0.0001). Age, sex, cigarette smoking history, diabetes mellitus and history of previous myocardial infarction were not associated with restenosis rate. Angina duration and severity before PTCA were also unrelated to restenosis rate. In summary, these variables, many of which have been previously implicated in restenosis, were not found to be predictors of restenosis. The decision to perform PTCA in individual patients should not be negatively influenced by the presence of these factors.

Restenosis following coronary angioplasty

The last decade has witnessed an enormous increase in the use and success of percutaneous transluminal coronary angioplasty. During this time, our knowledge of the mechanisms of angioplasty and of how it relates to the pathophysiology of restenosis has also grown. Despite our better understanding of the mechanisms responsible for it, restenosis remains a significant problem in coronary angioplasty, affecting approximately one third of patients. A variety of factors can affect the measured rate of restenosis, such as the symptomatic status of the patient and the timing of restenosis studies. Certain clinical, anatomic, and procedural factors are associated with increased rates of restenosis. Pharmacologic interventions are ineffective in preventing restenosis. A variety of new mechanical devices are being developed, but their efficacy at this time does not appear to be superior to angioplasty alone. While attempts at preventing restenosis have thus far been unsuccessful, the information gained through the various studies has added tremendously to our knowledge base of angioplasty. Through this better understanding of the mechanisms of angioplasty and restenosis, it is likely that the problem of restenosis will be improved, either through existing technology or by methods yet to be discovered.

Restenosis after transluminal coronary angioplasty: a risk factor analysis

In order to determine the relationship of restenosis following percutaneous transluminal coronary angioplasty (PTCA) to risk factors such as hypercholesterolemia, hyperglycemia, smoking, and weight, we performed a univariate analysis to test the association of these variables with restenosis in 723 patients who had percutaneous transluminal coronary angioplasty and follow-up catheterization. Cholesterol levels were higher in younger and female subjects (less than 0.0001). Initial cholesterol did not predict restenosis, and follow-up cholesterol levels showed an inverse relationship with restenosis (P less than .02). There was a trend (P less than .09) toward decreased restenosis in those who were active smokers at the time of follow-up catheterization. No differences were seen in diabetics with hyperglycemia, in both treated and untreated groups (P = NS). A stepwise multiple logistic regression was used to simultaneously test the association of the above risk factor variables to restenosis. None of the interactions were found to be significant, except cholesterol at follow-up (P = .001). Therefore, the status of serum cholesterol, blood sugar, smoking, and weight during the time of PTCA and at follow-up catheterization may be unimportant in predicting restenosis. Thus, we conclude 1) that to better determine the effect of these variables on restenosis, they should be estimated at times other than follow-up and 2) that the pathophysiological mechanism of restenosis may have different risk factors than progression of atherosclerotic coronary artery disease.

Relation to restenosis after percutaneous transluminal coronary angioplasty to vasomotion of the dilated coronary arterial segment

Among 868 patients with successful percutaneous transluminal coronary angioplasty (PTCA), 437 were restudied angiographically and had a provocative test with ergonovine during coronary angiography performed before and 6 months after the procedure. The relation between provoked coronary artery spasm and restenosis was studied and 4 groups of patients were analyzed. Those in group 1 (n = 63) had spasm before and after PTCA and their rate of restenosis was high (55%), especially when spasm after PTCA was observed on the dilated coronary segment (restenosis rate 58%). Patients in group 2 (n = 78) had spasm before PTCA but without abnormal vasoconstriction at 6 months and their incidence of restenosis was 19%. Sixty-one patients in group 3 had no spasm before PTCA but developed spasm at restudy. The rate of restenosis was high (38%) in this group, especially when the spasm after PTCA was located on the dilated segment (43%). In group 4 (n = 235), patients had no spasm before or after PTCA and the restenosis rate was 20%. Thus, the presence of coronary artery spasm on the dilated coronary segment, 6 months after a successful PTCA, is frequently accompanied (43% in group 3 and 58% in group 1) by restenosis.

Percutaneous transluminal coronary angioplasty: the second decade

Over the last decade, percutaneous transluminal coronary angioplasty has become a major therapeutic technique of myocardial revascularization. Advances in catheter design and operator experience have made angioplasty a viable alternative for many patients with both single- and multivessel disease who would otherwise require bypass surgery. Acute closure and restenosis remain the 2 principal limitations of angioplasty. Means of controlling these problems, including intracoronary stenting and antiplatelet and thrombolytic agents, are now being studied. Furthermore, controlled prospective randomized trials are underway to assess the value of angioplasty compared with coronary bypass surgery in the treatment of multivessel disease. These trials will help to establish the limits of coronary angioplasty and its relative advantages in terms of therapeutic results and costs.

Coronary angioplasty for unstable angina: immediate and late results in 200 consecutive patients with identification of risk factors for unfavorable early and late outcome

Two hundred patients (mean age 56 years, range 36 to 74) with unstable angina (chest pain at rest, associated with ST-T changes) underwent coronary angioplasty. In 65 patients with multivessel disease, only the "culprit" lesion was dilated. The initial success rate was 89.5% (179 of 200 patients). At least one major procedure-related complication occurred in 21 patients (10.5%): (death in 1, myocardial infarction in 16 and urgent surgery in 18). All patients were followed up for 2 years. Five patients died late; 8 had a late nonfatal myocardial infarction and 52 had recurrence of angina pectoris. The restenosis rate was 32% (51 of 158) in the patients with initial successful angioplasty who had repeat angiography. At the 2 year follow-up, after attempted coronary angioplasty in all 200 patients, the total incidence rate of death was 3% (one procedure related; five late deaths), of nonfatal myocardial infarction 12% (16 procedure related and 8 late after angioplasty), and 13% (26 patients) were still symptomatic although they had improved in functional class. Multivariate analysis showed that variables indicating an increased risk 1) for major procedure-related complications were: ST segment elevation, persistent negative T wave and stenosis greater than or equal to 65% (odds ratio 3.7, 3.7 and 3.3, respectively); 2) for angiographic restenosis were: presence of collateral vessels, ST segment depression, multivessel disease, left anterior descending coronary artery stenosis and history of recent onset of symptoms (odds ratio: 2.2, 2.0, 1.9, 1.9 and 0.54, respectively); and 3) for late coronary events (recurrence of angina, late myocardial infarction or late death) were: multivessel disease, total occluded vessel and ST segment elevation (odds ratio 3.7, 2.8 and 0.44, respectively). Thus, coronary angioplasty for unstable angina can be performed with a high initial success rate, but at an increased risk of major complications. The prognosis is favorable after initial successful coronary angioplasty.

Coronary artery spasm following coronary artery surgery

Coronary artery spasm during the early postoperative period following cardiopulmonary bypass for coronary artery surgery can be an unrecognized cause of sudden, severe cardiopulmonary collapse. The literature regarding perioperative coronary artery spasm is reviewed, and methods of prevention, diagnosis, and treatment are suggested. Preoperative angina at rest appears to be an important identifying factor in patients who experience postoperative coronary spasm. Anatomically, the presence of a relatively normal, dominant right coronary may also indicate increased risk for early post-coronary bypass spasm. Acute hypotension is often the first sign of coronary artery spasm, and conventional treatment methods may only worsen the vasospastic reaction. Peripheral intravenous nitroglycerin infusion has often been unsuccessful treatment while intragraft or intracoronary nitroglycerin injection or administration of calcium channel-blocking drugs, or both, has proven to be effective in reversing the coronary artery spasm and ventricular dysfunction. Reluctance to use vasodilating agents must be overcome, even in the face of hypotension, when evidence of spasm is present.

Percutaneous transluminal coronary angioplasty in patients with spasm superimposed on atherosclerotic narrowing

Of 552 patients undergoing percutaneous transluminal coronary angioplasty 102 had coronary artery spasm superimposed on atherosclerotic narrowing. Coronary angioplasty was successful in 97 (95%). The patients were discharged on a regimen of nifedipine (40-60 mg/day). Seventy six patients were symptom free 6-8 months after the procedure. Restenosis was detected in 35% of patients. Coronary artery spasm was provoked in 38 (44%) of the 87 patients who underwent an ergometrine maleate test. Twenty seven of the 34 patients with restenosis had a provocation test and coronary artery spasm was superimposed on restenosis in 22 (81.5%). Coronary angioplasty is feasible in patients with coronary artery spasm superimposed on atherosclerotic narrowing but the rate of restenosis is high and coronary artery spasm could have a role in the pathogenesis of restenosis.

Coronary wedge pressure: a predictor of restenosis after coronary balloon angioplasty

Coronary wedge pressure is the pressure recorded distal to a stenosis while the inflated balloon occludes the coronary artery during angioplasty. This pressure has been shown to reflect actual (visible) and potential (recruitable) collateral flow to the stenosed artery, distal to the angioplasty site. In 100 consecutive vessels (91 patients) for which coronary wedge pressure had been measured at the time of angioplasty, the long-term (7 +/- 3 months) angiographic results was evaluated. The overall angiographic restenosis rate was 37%. It was 52% (25 of 48) in arteries with a coronary wedge pressure greater than or equal to 30 mm Hg and 23% (12 of 52) in arteries with a coronary wedge pressure less than 30 mm Hg (p less than 0.01). The mean coronary wedge pressure was 30 +/- 10 mm Hg for vessels with restenosis and 26 +/- 9 mm Hg for those without restenosis (p less than 0.01). The prevalence of angiographically visible collateral flow was 42% and 29%, respectively (p = NS). Neither age, sex, presence of unstable angina, left ventricular function, number of diseased vessels nor initial and final transstenotic pressure gradient and degree of stenosis were significantly associated with the long-term outcome after angioplasty. Restenosis rate is significantly increased when coronary wedge pressure measured at the time of angioplasty is high (greater than or equal to 30 mm Hg). This suggests a negative influence of competitive collateral flow on long-term results of angioplasty.

Mechanism of angioplasty and its relation to restenosis

Balloon angioplasty enlarges atherosclerotic narrowings in the vast majority of patients in whom it is attempted at an acceptably low complication rate. Experimental and human pathologic studies have confirmed that angioplasty enlarges the lumen by stretching the vessel wall. Often this stretching process causes plaque fracture due to inelastic components of the atheroma. Denudation of the endothelium is also a consistent observation. While enlarging the lumen, this vascular trauma promotes marked platelet adhesion and aggregation that is dependent on the degree of vascular damage. Most platelets accumulate early within the first few hours. Subsequently, thrombus formation and smooth muscle cell proliferation can occur with the formation of a new fibrocellular occlusive process. Experimentally, antiplatelet therapy can significantly reduce platelet deposition and can reduce the incidence of restenosis. Although restenosis is a multifactoral process, prevention seems possible when platelet accumulation, thrombus formation and smooth muscle cell proliferation can be inhibited through drug or mechanical means.

Influence of the methodology of percutaneous transluminal coronary angioplasty on restenosis

Restenosis after percutaneous transluminal coronary angioplasty (PTCA) remains the principal factor preventing broader application of this form of myocardial revascularization. Several methodologic variables contribute to the quality of the angioplasty result and may directly or indirectly influence restenosis rates after the procedure. PTCA operators attempt to minimize thrombotic activity at the angioplasty site by delaying PTCA when thrombus is present, with heparin and antiplatelet agents and with thrombolytic agents if thrombus is identified during the procedure. Therapy directed at preventing coronary artery spasm with nitrates and calcium antagonists has no proven efficacy in preventing restenosis. Residual stenosis and pressure gradient have been shown to be predictors of restenosis. Retrospective studies have indicated that a balloon to artery diameter ratio greater than 1 favors long-term patency; however, preliminary results of a prospective randomized study suggested that acute complications were more frequent with larger balloons. The interplay of other balloon-related variables (maximal inflation pressure, number of inflations, duration of inflations, balloon material and length of balloon) and the potential influence on restenosis are discussed. Recommendations for patient management after PTCA are also offered. A number of prospective randomized trials using antiplatelet agents and modification of risk factors are underway to test ability of these strategies to influence restenosis.

Medical approaches to prevention of restenosis after coronary angioplasty

Although initial success rates for coronary angioplasty have improved, the rate of restenosis within 6 months of the procedure has persisted at 30 to 40%. The relation of restenosis to initial success, recurrence of symptoms and risk factors suggests that high grade or total lesions, long lesions, lesions in the proximal left anterior descending artery or in saphenous grafts, and the absence of intimal dissection after angioplasty are associated with an increased risk of restenosis. Unstable angina, male sex and diabetes are clinical factors associated with a greater risk of restenosis. Pathologic specimens suggest that plaque splitting and disruption are found acutely after angioplasty, but that restenosis occurs as an excessive reparative, proliferative response of smooth muscle cells leading to recurrent luminal narrowing. A prospective analysis of therapeutic interventions to prevent restenosis, such as administering antiplatelet and lipid-lowering agents, intensive diabetic therapy and administration of calcium antagonists, is proposed. Problems with timing of studies, design and sample size are considered. Current recommendations for anti-restenosis therapy include antiplatelet therapy before and after angioplasty, administration of heparin in some patients and intensive risk factor intervention for the 6 months after the procedure.

Recurrence of coronary artery spasm after successful percutaneous transluminal coronary angioplasty

A 47-year-old man presented with angina, and coronary angiograms showed a significant organic stenosis with spasm in the left anterior descending coronary artery. Percutaneous transluminal coronary angioplasty was successfully performed for the organic lesion in the left anterior descending coronary artery. Symptom of angina due to coronary artery spasm recurred, even without restenosis at the site of successful angioplasty.

Effect of nifedipine on recurrent stenosis after percutaneous transluminal coronary angioplasty

This double-blind, randomized study evaluated the effect of nifedipine on restenosis after coronary angioplasty. Two hundred forty-one patients with dilation of 271 coronary sites were randomized at the time of hospital discharge to receive nifedipine, 10 mg (123 patients), or placebo (118 patients) four times daily for 6 months. No patient was known to have coronary artery spasm. The mean duration of therapy was 4.4 +/- 2 (mean +/- SD) months for nifedipine and 4.3 +/- 2 months for placebo. A restudy angiogram was available in 100 patients (81%) in the nifedipine group and 98 patients (83%) in the placebo group. A recurrent coronary stenosis was noted in 28% of patients in the nifedipine group and in 29.5% of those in the placebo group (p = NS). The mean diameter stenosis was 36.4 +/- 23% for the nifedipine group and 36.7 +/- 23% for the placebo group (p = NS). By pill count, 78% of patients receiving nifedipine and 82% of those receiving placebo complied with the study drug regimen. Coronary stenosis recurred in 33% of patients in the placebo group and in 29% of patients in the nifedipine group who complied with the regimen and had angiograms (p = NS). In conclusion, the study did not demonstrate a significant beneficial effect of nifedipine on the incidence of recurrent stenosis after successful percutaneous transluminal coronary angioplasty.

Influence of a variant angina on the results of percutaneous transluminal coronary angioplasty

Nineteen (86%) of 22 patients with variant angina and important coronary stenoses (greater than 60%) had successful percutaneous transluminal coronary angioplasty. The acute complications in two patients were not caused by coronary spasms but by dissection with disturbance of perfusion. One of these two patients required a coronary bypass graft; the other was treated conservatively. Myocardial infarction developed in both patients. Despite long term administration of nifedipine (30-80 mg daily), restenoses occurred within six months (on average after 10 weeks) in nine patients with symptoms and one without. In four patients the restenoses exceeded the degree of stenosis before angioplasty. Five patients were revascularised by surgical means. Vessels in three out of four patients were later successfully dilated. After a mean period of observation of 24 months (6-51 months) 18 of the 19 patients are symptom free and do not require medication. The results confirm that angioplasty is an effective method of treating patients with variant angina and important coronary stenoses. The problem of the high frequency of restenosis, however, remains unresolved.

Comparative results of percutaneous transluminal coronary angioplasty in patients with dynamic versus fixed coronary stenosis

This study compares the results of percutaneous transluminal coronary angioplasty in a group of 132 patients (group A) with fixed atherosclerotic narrowing (no spontaneous or ergonovine-provoked spasm) and in a group of 97 patients (group B) with dynamic coronary stenosis (spasm superimposed on the stenosis). All these patients underwent complete follow-up angiography. The rate of restenosis (defined as a loss of 50% of the initial gain) was significantly higher in patients in group B (dynamic coronary stenosis) than in group A (fixed narrowing) (35 versus 22%, p less than 0.05). Despite treatment with a calcium antagonist, coronary artery spasm persisted in 44% of the patients in group B and was detected for the first time in 15% of the patients in group A. Thus, in patients with dynamic coronary stenosis, the results of coronary angioplasty were less satisfactory than in patients with fixed narrowing, and in both groups coronary artery spasm was frequently (64%) superimposed on the restenosis.

Incidence of spasm at the site of previous successful transluminal coronary angioplasty: effect of ergometrine maleate in consecutive patients

The incidence of coronary artery spasm at the site of previous successful angioplasty and its importance in leading to subsequent restenosis or recurrence of symptoms are unknown. Fourteen consecutive patients with single vessel coronary artery disease who had undergone successful percutaneous transluminal angioplasty were studied. All patients were given ergometrine maleate (ergonovine maleate) intravenously during repeat cardiac catheterisation six weeks to three months after angioplasty. Five patients demonstrated excessive luminal reduction (spasm) at the site of previous angioplasty that led to luminal stenoses ranging from 50% to 79%. Two of these patients developed chest pain and ST segment changes during ergometrine maleate provocation and they also showed maximal vasoconstriction. The remaining nine patients did not develop important luminal change at the site of angioplasty after ergometrine maleate. Ergometrine maleate administration resulted in less than or equal to 20% reduction in lumen diameter of adjacent apparently normal sections of the coronary arteries in all but two patients. At the site of previous angioplasty in the five patients with spasm, however, the lumen was constricted by a mean (SD) of 51 (12)%, whereas in the nine patients not demonstrating spasm mean reduction was 12 (7)%. Thus hypersensitivity to ergometrine maleate at the site of previous successful angioplasty was demonstrated in over a third of consecutive patients with single vessel coronary artery disease. The importance of this finding to long term results of coronary angioplasty needs to be investigated further.

Coronary artery spasm. What is its role in ischemic heart disease?

Knowledge of the pathophysiology of myocardial ischemia has been greatly enhanced recently by new information on coronary artery spasm. This phenomenon accounts for the mechanism underlying the attacks of resting chest pain in Prinzmetal's angina and plays a role in almost all aspects of ischemic heart disease. The diagnosis of coronary artery spasm can be made presumptively with noninvasive methods, but definitive documentation is usually obtained in the cardiac catheterization laboratory. The nitrate derivatives and the calcium antagonists provide a safe and effective approach to therapy.