Mervyn S. Gotsman

Prevention of Myocardial Damage in Acute Myocardial Ischemia by Early Treatment with Intravenous Streptokinase

We evaluated the effectiveness of early intravenous administration of 750,000 units of streptokinase in 53 patients with acute myocardial ischemia treated by a mobile-care unit at home (9 patients) or in the hospital (44 patients). Treatment was begun an average (+/- S.D.) of 1.7 +/- 0.8 hours from the onset of pain. Non-Q-wave infarctions developed subsequently in eight patients, whereas all the others had typical Q-wave infarct patterns. In 81 per cent of the patients the infarct-related artery was patent at angiography performed four to nine days after admission. Vessel patency was independent of the time of treatment, but residual left ventricular function was time dependent. Patients treated less than 1.5 hours after the onset of pain had a significantly higher ejection fraction (56 +/- 15 vs. 47 +/- 14 per cent; P less than 0.05) and infarct-related regional ejection fraction (51 +/- 19 vs. 34 +/- 20 per cent; P less than 0.01) and a lower QRS score (5.6 +/- 4.9 vs. 8.6 +/- 5.5; P less than 0.01) than patients receiving treatment between 1.5 and 4 hours after the onset of pain. Patients treated earlier by the mobile-care unit also had better-preserved left ventricular function than patients treated in the hospital. We conclude that thrombolytic therapy with streptokinase is most effective if given within the first 1.5 hours after the onset of symptoms of acute myocardial infarction.

Transradial approach for coronary angiography and angioplasty.

The transradial approach has currently been advocated as an alternative catheterization method for coronary angiography and angioplasty, due to the recent miniaturization of angioplasty equipment. The purpose of this study was to assess the practical clinical applicability of this method. From June to November 1994, 100 patients underwent coronary angiography and angioplasty with the transradial approach. Their mean age was 66.6 +/- 11.2 years, and 79 were men. In 4, radial puncture was not successful, and in 3, femoral access was necessary to complete the procedure. Coronary angioplasty was performed in 63 patients (76 lesions) with angiographic success (per lesion) of 96%. In 5 patients, a stent was successfully implanted. All patients were ambulatory on the day after the angioplasty procedure. In 98% of the patients, the introducer was taken out 1 to 4 hours after the procedure by local compression using a special custom-made device. No patient required blood transfusion. Major complications occurred in 2 patients; both had a cerebrovascular accident (1 probably not procedure-related), and both recovered. A radial pulse was palpated in 91 of the patients before discharge, and in 6 others, adequate flow could be heard with Doppler. In 2 patients, radial flow was restored within several weeks. None of the patients suffered from ischemia of the hand. Two patients had a small pseudoaneurysm successfully treated by local compression. Thus, coronary angioplasty can be performed safely using the transradial approach with relatively few vascular complications and with better patient comfort. However, the procedure is more time-consuming initially compared with the transfemoral approach due to a learning curve regarding equipment selection and catheter manipulation.

Right atrial thrombi are related to indwelling central venous catheter position: Insights into time course and possible mechanism of formation

We studied the effect of central line catheters on thrombus formation in the right atrium (RA), including the incidence and echocardiographic characteristics of the catheter-associated thrombus as well as possible clinical implications in patients. We prospectively studied 55 patients by transesophageal echocardiography within 1 week after Hickman catheter implantation and on a follow-up study at 6 to 8 weeks. We succeeded in imaging the catheter tip in 48 of the 55 patients (87%). In the baseline study 13 had the tip placed in the RA, eight at the superior vena cava-atrium junction, and 27 in the superior vena cava. An abnormal mass, consistent with a thrombus, was found in 12.5% of the patients, all of which were seen within the 13-patient (46%) group with the Hickman catheter tip placed in the RA. Hickman catheter insertion is associated with high incidence (12.5%) of early formation of RA thrombus. The formation of these thrombi is asymptomatic and highly associated (p < 0.001) with the catheter tip position in the RA, in contrast to their positioning in the superior vena cava or in its junction with the right atrium. On the basis of these findings, we recommend that special attention and effort be given to placing of the catheter tip in the superior vena cava and avoiding the RA during the implantation procedure.

Localization of lesions in the coronary circulation.

The location of coronary artery narrowings in coronary disease (CAD) is of considerable importance in assessing the mass of myocardium at risk as well as patient prognosis. The detailed distribution of coronary lesions was mapped in 302 patients with CAD who had coronary angiography for chest pain. All identifiable coronary lesions were measured manually and the site and degree of narrowing were stored in a computer-based multisegmental model of the coronary tree. A high prevalence of CAD was found in proximal vessels and especially at, or adjacent to, proximal points of branching. In the left anterior descending coronary artery, the lesions were most prevalent immediately after the first diagonal branch and at the origin of this branch. In the right coronary artery, there was a high prevalence of narrowing between the infundibular and acute marginal branches and specifically around the origin of the right ventricular branch. In the left circumflex coronary artery, there was a predilection for narrowing in and around the origin of the first marginal branch. When a ramus intermedius was present, its origin was frequently the site of narrowing.

Immediate Haemodynamic Effects of Verapamil in Man

The effect of the antiarrhythmic drug verapamil (Isoptin) on circulatory dynamics and myocardial contractility was studied in six patients in sinus rhythm: three patients were control subjects and three had underlying rheumatic valvular disease. The drug was given as an intravenous bolus (10 mg) and measurements made in the control state and repeated 1, 3, 5 and 10 min after administration of verapamil. Left ventricular (LV) systolic pressure fell by 18% 1 min after intravenous verapamil (p less than 0.01) and returned twoards the range of normal after 10 min. Heart rate increased and cardiac and stroke index were not altered 5 and 10 min after administration of the drug. Peak LVdp/dt and Vmax were reduced while LV end-diastolic pressure increased reflecting a decrease in LV contractility. The hemodynamic effects were similar in digitalised and nondigitalised patients.

Computer processing of artifact and arrhythmias in heart rate variability analysis

Analysis of heart rate variability (HRV) with Holter monitoring is often difficult due to excessive artifacts and arrhythmias. While short sudden surges are treated successfully by most methods, slow heart rate (HR) variations, nocturnal trapezoidally-shaped HR increases and special types of arrhythmias which are similar to normal HRV fluctuations may distort further time domain and spectral analysis. This paper examines the advantages and disadvantages of different methods for preprocessing of HR data. We have developed the following approach to the analysis of HRV. (1) A combination method based on the absolute difference between HR values and both the last normal HR value and an updated mean is used for removal of artifacts and arrhythmias. This method can detect both sudden surges in HR values as well as longer periods of noise combined with slow normal variations. An additional stage of wild point removal is then optionally applied. (2) Certain special problems such as large T-waves, bigeminal rhythm, slow HR variations and nocturnal trapezoidally-shaped HR increases are also identified. Although none of the algorithms can be applied successfully to all cases, the final computer analysis for preprocessing described in the present study has proved to be superior to the simplified methods which are usually used and provides more suitable data for HRV analysis.

Cardiovascular risk factor clustering and ratio of total cholesterol to high-density lipoprotein cholesterol in angiographically documented coronary artery disease

High levels of cardiac risk factors tend to cluster together and act synergistically. To develop a suitable and practical marker for clustering, we evaluated 380 consecutive patients at the time of coronary angiography. Analyses of lipid, rheologic, clinical and arteriographic profiles indicated a variety of interwoven relations. Because the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol (total/HDL cholesterol) was closely related to both the presence and extent of greater than or equal to 50% diameter reduction of greater than or equal to 1 coronary arteries, it was used to divide patients into quartiles. Clustering of high- and low-level risk factors was demonstrated in the highest and lowest quartiles of total/HDL cholesterol, respectively (p less than 0.001). The highest quartile may be characterized by an only moderately elevated total cholesterol level but patients in this quartile may have a very low HDL cholesterol level, high triglycerides, a tendency toward high hemoglobin and fibrinogen levels, a history of smoking, previous myocardial infarction and multivessel disease. These results suggest that total/HDL cholesterol serves as a marker not only for obstructive coronary disease but also for a cluster of potentially modifiable risk factors.

Early heart rate variability alterations after acute myocardial infarction.

In order to assess early changes in heart rate variability, we studied 81 patients with acute myocardial infarction during the initial 24 hours after thrombolytic therapy. The standard deviation of the mean heart rate and the low (0 to 0.05 Hz), mid (0.05 to 0.20 Hz), and high (0.20 to 0.35 Hz) frequency band power were evaluated with 24-hour ECG Holter recordings. We found diminished variance in the time domain and reduced power spectrum in the frequency domain compared with a group of 41 normal subjects (p < 0.01). Patients with anterior infarction had significantly (p < 0.01) higher heart rates and lower heart rate variability values than patients with inferior infarction. Reduction in heart rate variability occurred within the first 8 hours in patients with anterior infarction; a significant fall (p < 0.03) was especially noted in the high-frequency band after a decline in ST-segment elevation. Heart rate variability alterations in patients with inferior infarction were most evident in the final 8-hour interval. These findings may be viewed in terms of sympathovagal imbalance and may be related to clinical signs of intense autonomic nervous system activity that are observed early in the course of acute anterior and inferior myocardial infarction.

One-Stage Coronary Angiography and Angioplasty

The combination of diagnostic angiography and angioplasty as a single procedure is becoming common practice in many institutions, but the feasibility and safety of this strategy have not been reported. This report describes 2,069 patients who underwent coronary angioplasty over a 3-year period at an institution where combined angiography and angioplasty is the norm. All patients were prepared before angiography for potential immediate angioplasty. In 1,719 patients, angioplasty was performed immediately after the diagnostic angiogram, while separate procedures were performed in 350 patients. Of those 350 patients, 254 were referred for angioplasty after diagnostic angiography at other hospitals. One thousand one hundred ninety-seven patients were admitted electively for treatment of stable angina pectoris, and 872 underwent procedures during hospitalization for unstable angina or acute myocardial infarction. One thousand nine hundred seven patients (92.2%) had successful angioplasties; in 130 patients (6.3%) the lesion could not be dilated, but no complication occurred, and in 32 patients (1.5%) angioplasty ended with a major complication (0.8% death, 1.0% Q-wave myocardial infarction, 0.5% emergency coronary artery bypass surgery). There was no difference between the combined and staged groups with regard to success, major and minor complication rates or in length of hospitalization after angioplasty. We conclude that routine combined strategy for angiography and angioplasty is feasible, safe, easier for the patient, and more cost-effective than 2 separate procedures.

Clinical and angiographic predictors of immediate recoil after successful coronary angioplasty and relation to late restenosis

The effect of immediate recoil on the results of balloon angioplasty was examined in a group of 416 patients (596 lesions) who underwent successful coronary angioplasty. Immediate recoil was responsible for loss of 0.42 +/- 0.64 mm from the potentially achievable lesion diameter, and represented 23% of the actual gain in diameter. The immediate recoil was determined mainly by the degree of arterial stretch, which is best represented by the balloon to normal artery size ratio (correlation coefficient 0.49, p < 0.0001). Classic risk factors for coronary artery disease did not affect immediate recoil, except for a trend toward lower values in patients with history of hypercholesterolemia. There was a tendency for lower recoil in patients with residual coronary thrombus and in those who underwent angioplasty within 1 week of acute myocardial infarction. Recoil was larger in the left anterior descending artery than in the circumflex or the right coronary artery. Patients with more immediate recoil developed more restenosis (> 50% stenosis at follow-up). However the late loss of luminal diameter due to the restenotic process was smaller in those who had larger initial recoil. It is concluded that immediate recoil after balloon angioplasty is an elastic phenomenon that is related mainly to the degree of arterial stretch. The relative importance of immediate recoil in determining the late outcome of coronary angioplasty is at least as important as the late restenotic process.