Emergency coronary bypass surgery after coronary angioplasty: the national heart, lung, and blood institute''s percutaneous transluminal coronary angioplasty registry experience

The frequency and outcome of emergency CABG for complications of PTCA in the NHLBI PTCA Registry were analyzed. Emergency surgery was performed in 202 patients (6.6%). The most frequent indications for emergency operation were coronary dissection in 46%, coronary occlusion in 20%, prolonged angina in 14% and coronary spasm in 11%. Emergency surgery was most often necessary in patients in whom lesions could not be reached or traversed, but more than 25% of patients who required emergency surgery had initially successful dilatation followed by abrupt reclosure of the vessel. The mortality rate with emergency CABG was 6.4%, and nonfatal Ml occurred in 41% of patients, with Q waves developing in approximately 60% of patients with MI. However, 53% of patients managed with emergency CABG for severe ischemic events with PTCA did not have evidence of MI or die and had an uncomplicated postoperative course. No baseline clinical predictors of emergency surgery were identified. Lesion eccentricity was associated with a significant increase in frequency of emergency operation, and the incidence of emergency surgery declined with increasing experience with PTCA.     

Efficacy of percutaneous transluminal coronary angioplasty: Technique,patient selection,salutary results,limitations and complications

Percutaneous transluminal coronary anglopiasty (PTCA) was performed in 25 patients and 29 vessels during a 12-month period. In six additional patients scheduled for PTCA, the procedure was cancelled when repeat angiography identified progression to occlusion, coronary spasm, or other adverse factors not previously apparent. PTCA was successful in 14 of 25 patients (56%) and in 18 of 29 vessels (62%); success was associated with clinical improvement in all patients by symptomatology, exercise testing and/or myocardial radionuclide imaging. Beneficial results were particularly achieved with left anterior descending artery lesions and with stenoses showing less than 90% narrowing. One peripheral arterial complication occurred and no patients required emergency surgery. While coronary dissection was detected angiographically in four patients and evidence of coronary spasm was present in three patients post-PTCA, neither was accompanied by untoward early clinical events. Multivessel dilatation in three patients was initially successful but symptoms returned in two during follow-up. Restenosis developed in 3 of 14 patients (21%) after 3 months. Our experience indicates (1) that the specific vessel attempted and lesion severity particularly influence the liklihood of success, (2) the not infrequently induced coronary dissection or spasm does not necessarily represent a serious complication, and (3) angiography repeated in preparation for PTCA identifies a significant minority of patients who are no longer candidates.     

Effects of intracoronary streptokinase in acute myocardial infarction

Intracoronary streptokinase (SK) was administered to 11 patients with evolving acute transmural myocardial infarction 5.5 ± 0.4 hours from the onset of symptoms. Ten patients (91%) had total coronary occlusion, and one had subocclusion of the vessel corresponding to the ECG site of infarction. Intracoronary nitroglycerin failed to restore patency of total occlusion in all patients. In 9 of 11 patients (82%), patency was restored or improved with intracoronary SK. Thrombolysis was successful in 8 of 11 patients (73%), and one patient with transient patency developed acute reocclusion. Average time from SK infusion to reperfusion was 24 ± 7 minutes. Patients with successful thrombolysis had patency initially restored at a dosage of 61,000 ± 15,000 IU of SK and received a total dosage of 136,000 ± 17,000 IU. Patency persisted at late study in six of eight patients, and two patients developed late reocclusion. Successful thrombolysis was associated with significant improvement in left ventricular ejection fraction (LVEF) from early to late study, in contrast to deterioration of LVEF in patients with unsuccessful recanalization (p < 0.001). Systemic fibrinolytic activity occurred in 8 of 11 patients at a mean dosage of 125,000 ± 15,000 IU of SK and was unassociated with significant bleeding. Significant decrease in hemoglobin concentration in the early hospital phase occurred in patients receiving SK but did not differ from decreases occurring in a matched control population receiving conventional therapy for infarction. Thus intracoronary thrombolysis with SK was successful in the majority of patients during the early phase of evolving transmural infarction, and successful thrombolysis was associated with significant improvement in LVEF. Systemic fibrinolysis occurs in most patients despite small total doses of SK, and the significant decrease in hemoglobin in these patients may be unrelated to SK, since similar changes occurred in a control population receiving conventional therapy.     

The oxygen free radical system: potential mediator of myocardial injury

The sequential univalent reduction of oxygen gives rise to very reactive intermediate products including superoxide anion radical, hydrogen peroxide and free hydroxyl radicals. Normally, the tissue concentration of these intermediate products of oxygen is severely limited; however, if oxygen free radicals are produced in excess of the capacity of the tissues to eliminate them, they may cause serious damage. The biochemistry and possible sources of free radical generation in animal models of ischemic/reperfusion injury are reviewed. The ability of scavengers of oxygen free radicals to improve mechanical, mitochondrial and sarcoplasmic reticulum function in animal models of ischemic/reperfusion injury suggests that oxygen free radicals are partly responsible for myocardial injury in these models. Future research should be directed at establishing the relevance of oxygen radical-mediated myocardial injury in the experimental setting to analogous clinical situations.     

Arrhythmias on ambulatory electrocardiographic monitoring in women without apparent heart disease

Cardiac arrhythmias were evaluated in apparently normal women by randomly selecting within the age decades of 20 to 60, 200 of the 788 women employees of a company. After exclusions for cardiac and medical reasons and refusals to participate, 101 subjects underwent 24-hour ambulatory electrocardiographic monitoring. The mean heart rate was 82 beats/min, but was higher in smokers (p < 0.05). Premature supraventricular contractions were present in 28 of 101 subjects (28 %); the prevalence increased with age (p < 0.001), but the frequency was less than 1 per hour in 24 of 28. PVCs occurred in 34 of 101 subjects (34%); the frequency was less than 1 per hour in 25 of 34. The PVCs were complex (Lown grade 3 or higher) in 10 (10%) and multifocal in 9 of 10; there was 1 couplet each in 3 and 1 run of 4 PVCs in 1 subject. PVCs were present in 20 of 42 subjects (48%) taking any medication (primarily oral contraceptives, estrogenic hormones and maintenance thyroid), compared with 14 of 59 subjects (24%) not taking medication (p < 0.01). In women younger than 40 years, PVCs were present in 8 of 15 women (53%) taking contraceptives, compared with 4 of 33 (12%) not taking contraceptives (p < 0.001). PVCs occurred in 7 of 12 subjects (58%) taking thyroid medication, compared with 27 of 89 (30%) not taking thyroid medication (p < 0.03). In the 59 subjects not taking medication only 1 subject averaged more than 1 PVC/hour and 1 had 1 couplet. Thus, the prevalence and frequency of cardiac arrhythmias were low in randomly sampled, apparently normal women; however, the prevalence of PVCs was significantly lower in subjects not taking medication.     

Angiographic changes produced by percutaneous transluminal coronary angioplasty

Percutaneous transluminal coronary angioplasty (PTCA) is being used with increasing frequency in the treatment of patients with symptomatic coronary artery disease. Balloon inflation results in diverse angiographic findings, reflecting the great variety of anatomic and pathologic changes produced. The long-term effects of inflation on the underlying atherosclerotic lesion and the clinical outcome are unknown but may depend in part on the anatomic changes caused by the dilatation itself. To facilitate communication and evaluation of the results of PTCA, a classification of the angiographic findings and their potential mechanisms is presented. Recognition and analysis of these angiographic findings may be helpful in evaluating the long-term outcome of patients undergoing PTCA.     

Natural history of patients with single-vessel disease suitable for percutaneous transluminal coronary angioplasty

To permit comparison of percutaneous transluminal coronary angioplasty (PTCA) with conventional therapy, the clinical outcome was established in patients who would have been suitable candidates for PTCA but who presented before the technique was available. Coronary angiograms were reviewed of patients who met the following criteria: single-vessel disease with proximal subtotal coronary stenosis, chest pain of at least class II, and cardiac catheterization before 1981. Angiograms were evaluated according to established criteria for PTCA by an experienced angiographer. One hundred ten patients (2.1% of the patient population) were judged suitable for PTCA. Clinical and catheterization findings closely resembled those of patients in the national PTCA registry. Five years after catheterization, 97% of PTCA candidates treated medically were alive and 85% had not had myocardial infarction. Forty-six patients had coronary artery bypass surgery within 6 months of catheterization and 10 other patients had subsequent surgery. Five years after surgery, 91% were alive and 87% had not had myocardial infarction. At 6 months of follow-up, 78% of all patients had improved at least 1 functional class, and 86% of all patients working before catheterization were still employed. Functional capacity was well maintained during long-term follow-up (median 6.5 years, range 1.4 to 12.2). These data indicate that PTCA candidates have an excellent prognosis for survival, a low risk of infarction, and well-maintained functional capacity when revascularization is reserved for those with inadequate control of symptoms by medical therapy.     

Improvement of left ventricular function after percutaneous transluminal coronary angioplasty

Cardiac function and left ventricular dynamics were measured in seven consecutive patients 1 day before and 6 months after percutaneous transluminal balloon angioplasty of subtotal proximal stenosis of the left anterior descending coronary artery. Before angioplasty all patients had obvious left ventricular dysfunction during exercise and to a smaller degree during isoproterenol infusion; the condition of all patients was greatly improved 6 months after angioplasty. After angioplasty, left ventricular end-diastolic pressure was normal at rest and decreased from a mean (± standard error of the mean) of 33.8 ± 1.6 to 19.2 ± 0.5 mm Hg on exercise. Left ventricular ejection fraction, measured by a gated blood pooling technique with technetium-99m, improved on exercise from 46 ± 5.0 percent to 69 ± 1.0 percent. Cardiac output and stroke volume index increased significantly with exercise after angioplasty. The peak negative rate of pressure reduction in the left ventricle (dP/dt/min), an index of left ventricular relaxation, was highly abnormal on exercise before (2,307 ± 260 mm Hg/s) and increased to the normal range (3,154 ± 200 mm Hg/s) after angioplasty. The improvement in left ventricular function after transluminal angioplasty in these cases of proximal left anterior descending coronary arterial stenosis is extremely encouraging.     

Efficacy of repeat percutaneous transluminal coronary angioplasty for coronary restenosis

The short- and long-term outcome of patients within the NHLBI PTCA Registry who underwent repeat PTCA for coronary restenosis were analyzed. Of 1,880 patients in whom an initial PTCA was successful, 203 had a repeat PTCA attempted after restenosis developed. Repeat PTCA was usually performed within 6 months of the first procedure. The success rate of repeat PTCA was 85.2%. As a direct result of repeat PTCA, 1.5% of patients had an MI and 2% required emergency CABG. No patien died as a result of the attempted second procedure. One to 3 years of follow-up information was available in 94% of eligible patients. Most patients (75,9%) did not have a subsequent (third) PTCA, CABG or an MI. The late mortality rate was 0.8%. Angiographic follow-up information was available in 62 patients. Sustained enhancement of the diameter of the redilated lesion was observed in 66%. Thus, repeat PTCA has a high success and a low complication rate. Most patients did not have subsequent restenosis and are free of angina. Hence, repeat PTCA should be recommended for patients who have restenosis and should be considered as an integral component of PTCA therapy.     

Surgical intervention for failed percutaneous transluminal coronary angioplasty

From July 1978 through April 1983, 125 patients underwent attempted PTCA at the Massachusetts General Hospital. The first 25 patients were considered to be surgical candidates after failure of the PTCA attempt regardless of the presence of acute myocardial ischemia (Group I). The subsequent 100 patients (Group II) were considered to be surgical candidates only if acute myocardial ischemia was caused by a failed PTCA attempt. Four of the Group I patients (16%) required urgent operative intervention and 7 of the Group II patients (7%) required urgent operative intervention yielding, a total of 11 patients (8.8%) of the entire group. There were no hospital deaths and only 1 MI, actually documented before cardiopulmonary bypass. Women required urgent operative intervention more frequently than men (14.7% vs 6.6%). Patients with right coronary artery lesions required urgent operative intervention more often than those with left anterior descending lesions (13.0% vs 8.0%). Factors that lead to low operative mortality and myocardial infarction rates include an available operating room and team during the PTCA attempt, systemic arterial and Swan-Ganz pulmonary artery catheter pressure measurements at the time of angioplasty, intraaortic balloon pumping at the first sign of myocardial injury and expeditious surgery.     

Limited B cell regeneration in a B cell deficient rat model: Studies with dexamethasone

Neonatal rats treated with streptozotocin (SZ) at 2 days of age show a transient hyperglycemia with regeneration of B cells that parallels the recovery of normoglycemia. However at 6 wk of age, these animals develop non-ketotic hyperglycemia suggesting that the regeneration of B cells after the early SZ treatment was insufficient and limited. To test the replicative capacity of the B cells in this model, we tried to induce additional replication with a 13 day treatment of pharmacological amounts of the glucocorticoid, dexamethasone. Dexamethasone treatment led to a marked increase of plasma glucose in SZ-treated rats (196 ± 23 mg/dl pretreatment versus 428 ± 30 mg/dl post-treatment), while not affecting that of the normal littermates. Plasma insulin concentrations were increased in both groups. Pancreatic insulin concentration was increased by the glucocorticoid in the normal non-SZ rats, whereas no increase in the already low insulin concentrations were found in the SZ group. In a similar fashion, dexamethasone produced an increase in the B cell number/islet of the non SZ animals, but no increase in the reduced B cell number of the SZ rats. These data therefore provide further evidence for a limitation in the capacity for B cell replication in this model. With regard to other islet peptides, dexamethasone did not cause a significant change in plasma glucagon concentrations. Pancreatic glucagon concentration, which was reduced in the SZ rats, was normalized with glucocorticoid treatment. Pancreatic somatostatin concentration was similar in both the non-SZ and SZ groups, and increased following dexamethasone in both of these groups. In contrast glucocorticoid led to a fall in the somatostatin concentration of the gastric antrum in both groups. Thus the effects of dexamethasone upon pancreatic and gastric somatostatin concentrations are divergent. The mechanisms responsible for the changes in glucagon and somatostatin tissue content remain unclear.     

Assessment of percutaneous transluminal coronary angioplasty by quantitative coronary angiography: Diameter versus densitometric area measurements

Cineangiograms of 138 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) were analyzed with a computer-based coronary angiography analysis system. The results before and after dilatation are presented. In a first study group (120 patients), the severity of the obstructive lesions derived from the automatically detected contours was evaluated in absolute terms and in percent-diameter reduction. In a second group of patients, 18 coronary lesions were selected for their extreme severity and symmetric aspect before angioplasty as assessed from multiple views. In the second group, the densHometric percent-area stenosis was used to assess the changes in cross-sectional area after PTCA and was compared with the circular percent-area stenosis computed from the diameter measurements. Before PTCA, a good agreement exists between the densitometric percent-area stenosis and the circular percent-area stenosis. After PTCA, important discrepancies between these 2 types of measurements are observed. It is suggested that these discrepancies in results after PTCA can be accounted for by asymmetric morphologic changes in luminal cross section, which cannot be assessed accurately from diameter measurements in a single-plane view.     

Natural history of Wolff-Parkinson-White syndrome discovered in infancy

The prognosis of 20 infants with a diagnosis of Wolff-Parkinson-White syndrome under 1 year of age is presented. Children were followed up from 1 to 19 years (mean 9 years). Seven patients had associated congenital heart disease. Analysis of the associated arrhythmias revealed episodes of supraventricular tachycardia in 18 (90 percent). During paroxysmal supraventricular tachycardia the QRS complex was normal in seven and wide in nine children. Categorizing patients into groups according to the width of the QRS complex and the presence or absence of a delta wave during tachycardia helps in understanding and planning therapy. Eighteen patients had a stable or improved course with growth but two patients with tetralogy of Fallot died postoperatively with resistant supraventricular tachycardia. The high prevalence rate of supraventricular tachycardia during infancy which later decreases or disappears could be explained by the different electrophysiologic responses between normal and accessory pathways during the fast heart rate characteristic of this young age.Invasive electrophysiologic studies are indicated in children older than 1 year of age who remain symptomatic and in all children being conconsidered for cardiac surgery regardless of the effectiveness of the preoperatlve therapy.     

Measurement of red cell velocity with a two-slit technique and cross-correlation: Use of reflected light,and either regulated dc or unregulated ac power supplies

The data illustrate red cell velocity values obtained from microvessels of brain and muscle by utilizing a two-slit technique and cross-correlator in settings employing reflected light. Similarities are shown between these data and data obtained or reported from transilluminated vessels. These similarities include relative independence of apparent centerline velocities on the plane of focus, and relatively low ratios of velocities at the center to velocities near the wall. It is shown, in addition, that accurate velocity measurements can be made utilizing a nonregulated ac power supply, although it cannot be stated that such measurements could be obtained in circumstances other than those described.     

Coronary hemodynamics during percutaneous transluminal coronary angioplasty

The hemodynamic consequences of multiple transient occlusions (9.8 ± 3.7 seconds) of the left anterior descending coronary artery were assessed in 15 conscious patients during percutaneous transluminal coronary angioplasty. Thermodilution coronary venous blood flow, measured in the great cardiac vein, decreased from control values of 75.9 ± 24 ml/min to 50.9 ± 21.9 with coronary occlusion (probability [p] < 0.00001) and increased to 101.6 ± 34.3 after release of occlusion (p < 0.00001). Changes in coronary sinus blood flow, measured simultaneously, reflected the alterations in the great cardiac vein. Restoration of postocclusion blood flow to control values occurred in 18.2 ± 6.7 seconds, and is compatible with reactive hyperemia rather than sustained improvement in resting coronary blood flow. Flow repayment during reactive hyperemia exceeded flow debt incurred during coronary occlusion by 288.4 ± 106 percent (p < 0.05). The increase in reactive hyperemic flow after initial coronary occlusion (24.2 ± 15.7 ml/min) was less than that after final occlusion (42.2 ± 10.1, p < 0.05). This suggests an initial limitation of reactive hyperemia by persistent coronary stenosis. In all patients, reactive hyperemia accentuated the trans-stenotic coronary ostial to distal coronary arterial pressure gradient. Compared with a control value of 53.5 ± 7.7 percent, the great cardiac vein oxygen saturation transiently decreased to 49.3 ± 7.0 percent (p < 0.001) on release of the occlusion and then increased to 62.5 ± 5.2 percent (p < 0.001) during reactive hyperemia. A small reduction in aortic pressure from 96.4 ± 10.2 mm Hg to 89.9 ± 10.9 mm Hg(p < 0.00001) was observed during occlusion. A reduction in first derivative of left ventricular pressure (dP/dt) during coronary occlusion, in three patients in whom it was measured, suggests that the decrease in systemic pressure is due to transient ischemic myocardial dysfunction rather than to peripheral arteriolar vasodilation. These observations are relevant to the performance of coronary angioplasty, and to the understanding of the physiology of transient coronary occlusion in conscious patients.     

Exercise, electrocardiographic and functional responses after percutaneous transluminal coronary angioplasty

Exercise testing after successful PTCA showed improved cardiac functional status on examination of electrocardiographic and symptomatic responses, myocardial perfusion and global and regional left ventricular function. Sixty-six patients were studied before and after persistently successful PTCA. Follow-up studies an average of 8 months after the successful procedure showed an incidence of abnormal testing of only 7% using both electrocardiographic and subjective symptomatic criteria during treadmill studies and no abnormal studies with thallium scintigraphy. Radionuclide cineangiography demonstrated similar left ventricular ejection fractions at rest before and after PTCA, but an improvement of 9 ± 10% (p < 0.001) in the exercise ejection fraction at follow-up. However, 52% of patients with paired data still had an abnormal radionuclide cineangiographic study after successful PTCA, raising the question of the presence of subclinical ischemia or a false-positive result.     

Return to work after coronary angioplasty: A report from the national heart, lung, and blood institute percutaneous transluminal coronary angioplasty registry

Employment status was analyzed in 2,250 patients enrolled at 65 clinical centers in the NHLBI PTCA Registry. Patients were classified into 3 groups depending on the outcome of PTCA. In 63.6%, PTCA was successful without MI or CABG (Group A); in 25.3%, PTCA was unsuccessful and was followed by CABG (Group B); and in 11.1%, PTCA was unsuccessful and was followed by medical therapy alone (Group C). At entry, 68.3% of all patients were employed full- or part-time. The clinical characteristics of the 3 groups were different. Patients in Group C had a higher incidence of previous MI and previous CABG. In addition, patients in Group C had a significantly decreased baseline employment rate compared with those in Group A. At a mean follow-up of 1.5 years, there was a small but similar decrease in the percentage employed fullor part-time in all groups.

Employment status also was analyzed in a subset of 1,150 patients working full- or part-time at baseline and aged 60 years or younger, who would be expected to have the highest return to work rates. At a mean follow-up of 1.4 years, 81 to 86% of patients remained working irrespective of the outcome of PTCA. However, patients with successful PTCA returned to work significantly sooner. The occurrence of chest pain during follow-up in these patients was an important predictor of return to work, irrespective of the outcome of dilatation. In patients with chest pain during follow-up, only 77% were working, compared with 90% of patients who had not had chest pain.