Morphologic observations after percutaneous transluminal balloon angioplasty of early and late aortocoronary saphenous vein bypass grafts.

Clinical and morphologic observations from two patients undergoing percutaneous transluminal angioplasty of stenotic aortocoronary saphenous vein bypass grafts early (3 months) and late (56 months) after graft insertion are described. Each patient had one or more clinically successful graft dilations resulting in an angiographic increase in luminal diameter and a decrease in mean trans-stenotic gradient, and each had restenosis of the graft at the site of previous angioplasty within 2 months of dilation. Both operatively excised grafts had diffuse but variable amounts of intimal fibrous thickening and severe narrowing at the previous angioplasty site. The early graft had no evidence of dilation injury, and the intimal thickening consisted solely of fibrocollagenous tissue free of calcific deposits. In contrast, the late graft had a healing intimal dissection at the angioplasty site, and the intimal thickening consisted of atherosclerotic plaque with calcific deposits. Angiographic and morphologic correlations suggest that the mechanism of saphenous vein angioplasty early (less than or equal to 1 year) after insertion is by graft "stretching," while late (greater than 1 year) after insertion it is by atherosclerotic plaque "fracture" similar to that observed in atherosclerotic coronary arteries subjected to angioplasty procedures.

Atrioventricular and intraventricular conduction in hyperkalemia.

Twelve patients exhibited electrocardiographic evidence of fascicular block during hyperkalemia. Isolated left posterior hemiblock occurred in four, isolated left anterior hemiblock in two, right bundle branch block with left anterior hemiblock in two, right bundle branch block with left posterior hemiblock in one, left bundle branch block with abnormal left axis deviation in two and advanced atrioventricular block in one. In all seven patients with sinus rhythm the P-R interval shortened after correction of hyperkalemia. Electrophysiologic studies using His bundle recording and atrial pacing in one patient revealed intraatrial conduction delay and marked prolongation of conduction time in the His-Purkinje system. It is concluded that conduction defects in the specialized intraventricular conduction system are common in hyperkalemia and result in electrocardiographic patterns of fascicular block.

Early and late morphologic changes in major epicardial coronary arteries after percutaneous transluminal coronary angioplasty.

Certain clinical and morphologic observations are described in 4 men who had PTCA of the left anterior descending coronary artery early (4 hours) or late (80, 90 and 150 days) before sudden death. Histologically, each of the 4 patients had the site of PTCA narrowed 76 to 95% in cross-sectional area by atherosclerotic plaque. The early PTCA patient had coronary artery dissection at the site of PTCA. Each of the 3 late PTCA patients had a decrease in the mean transstenotic coronary gradient (17, 38 and 43 mm Hg) and an angiographic increase in the left anterior descending coronary artery luminal diameter (55, 60 and 65%) at the time of PTCA. At necropsy, 80, 90 and 150 days later, the LAD coronary artery in the area of the PTCA in each patient was narrowed 76 to 95% in cross-sectional area by plaques. No cracks in plaques or other lesions that may have resulted from PTCA were identified histologically in the left anterior descending coronary artery in any late PTCA patient.

Status of the major epicardial coronary arteries 80 to 150 days after percutaneous transluminal coronary angioplasty. Analysis of 3 necropsy patients.

Certain clinical and necropsy cardiac findings are described in 3 men who had percutaneous transluminal coronary angioplasty (PTCA) of the left anterior descending (LAD) coronary artery 80, 90, and 150 days before sudden death. Each patient had a decrease in the mean transstenotic coronary gradient (17, 38, and 43 mm Hg) and an angiographic increase in the LAD luminal diameter (55, 60, and 65%). At necropsy, the LAD coronary artery in the area of the PTCA in each patient was narrowed 76 to 95% in cross-sectional area by atherosclerotic plaques. No cracks in plaques or other lesions which may have resulted from the PTCA procedure were identified histologically in the LAD coronary artery of any patient.

Arrhythmias in the post CCU phase of myocardial infarction: their correlation with the acute illness.

To estimate the frequency of potentially life-threatening arrhythmias in myocardial infarction following transfer from the coronary care unit (CCU) and to identify features of the acute illness which predict such events, 66 patients were monitored on-line by means of a computer assisted system. Premature ventricular contractions (PVCs) were detected following transfer from the CCU in 64 patients (97%). In 29 (44%) they fell in classes 2 to 4 of Lown. Accelerated ventricular rhythm was detected in five and ventricular tachycardia in three. The presence of these rhythm disturbances did not correlate with age, sex, infarct location, the occurrence of previous infarction, the level of serum cardiac enzymes, the presence of heart failure, atrial arrhythmias, heart block, or serious ventricular arrhythmia in the CCU. Use of procaine amide or quinidine for persistent ventricular arrhythmia in the CCU was correlated with detection of class 2, 3 or 4 PVCs. Thus, PVCs are nearly universal in the late phase of hospitalization for myocardial infarction. Frequent and complicated PVCs are common and occur most frequently in individuals in whom such events have been persistent in the CCU.

Electrocardiographic radiotelemetry in the early recuperative period of acute myocardial infarction. Its value in detecting arrhythmias in the setting of a progressive coronary care unit.

One hundred seventeen consecutive patients with acute myocardial infarction transferred from the coronary care unit to a progressive coronary care unit were monitored by electrocardiographic radiotelemetry for a median of five days for arrhythmia detection. Eighty patients (68%) had arrhythmias; 37 patients (32%) had none. Almost all arrhythmias were detected by the sixth day of monitoring. Thirty-nine patients (33%) had premature ventricular contractions, two patients had primary ventricular tachycardia, one patient had primary ventricular fibrillation, and two patients had secondary ventricular fibrillation. An additional patient was successfully resuscitated after monitoring had been discontinued. Four (3%) of 117 patients had a potentially lethal arrhythmia treated successfully, three while being monitored. Twenty-five of the patients (21%) had 33 episodes of treatment intervention because of telemetrically detected events. Five patients (4%) died, all of unpreventable causes. No patient died because of an arrythmia. We conclude that telemetry is feasible and practical in detecting arrhythmias. It is clear that potentially fatal ventricular arrhythmias do occur following transfer from the coronary care unit and that monitoring is, therefore, desirable.

Morphologic observations in coronary arteries, aortocoronary saphenous vein bypass grafts, and infant aortae following balloon angioplasty procedures.

Morphologic observations following transluminal balloon angioplasty are summarized from eight adult patients undergoing coronary or saphenous vein bypass graft angioplasty and from an infant with aortic valve stenosis angioplasty. Possible mechanisms of dilation injury and complications of balloon bursting are discussed.

Dose-ranging study with a new two-chain rt-PA in patients with acute myocardial infarction: a multicenter trial.

Tissue-type plasminogen activator (t-PA) derived from a melanoma cell line was first used in patients with acute myocardial infarction in the early 1980s. Recombinant DNA technology then allowed production of large amounts of t-PA. The TIMI-I trial used a two-chain recombinant (rt-PA) product. A predominantly single-chain rt-PA (alteplase) was used in the majority of the TIMI II trial. The present study used a different form of two-chain rt-PA (duteplase) to determine the effective dose for thrombolysis at 60 min, and to evaluate time to reperfusion, reocclusion at 72-96 h, coagulation profiles, and bleeding events. Duteplase was given intravenously to 75 patients a mean of 3.8 +/- 1 h after the onset of myocardial infarction. Following angiography demonstrating coronary occlusion, 23 patients received a low dose of duteplase [0.16-0.29 million international units per kilogram (MIU/kg)] over 60 min followed by a 5-h infusion in conjunction with heparin, 25 patients received a middle dose (0.30-0.41 MIU/kg) and 23 patients received a high dose (0.43-0.74 MIU/kg). Angiography was then performed every 15 min x 4. Progressive recanalization occurred over 60 min (median 45 min) with an overall success rate of 59% (mean 60-min dose: 0.37 MIU/kg). No dose-response relationship was observed. The reocclusion rate was 9% at 72-96 h. Reductions in fibrinogen and plasminogen correlated with dose, but clinical events did not.(ABSTRACT TRUNCATED AT 250 WORDS)