Delayed preconditioning-mimetic action of nitroglycerin in patients undergoing coronary angioplasty.

BACKGROUND: Experimental studies suggest that the cardioprotective effects of the late phase of ischemic preconditioning (PC) can be mimicked pharmacologically. However, to date, no drug has been tested with respect to its ability to elicit a late PC effect in humans. As a consequence, clinical exploitation of the powerful anti-stunning and anti-infarct actions of late PC has been elusive thus far. METHODS AND RESULTS: A total of 66 patients were randomized to receive a 4-hour intravenous infusion of nitroglycerin (NTG) or normal saline; on the following day, they underwent percutaneous transluminal coronary angioplasty (three 2-minute balloon inflations 5 minutes apart). Measurements of ST-segment shifts (intracoronary and surface ECGs), regional wall motion (quantitative 2D echocardiography), and chest pain score indicated that the infusion of NTG 24 hours before angioplasty rendered the myocardium relatively resistant to ischemia and that the degree of this cardioprotective effect was comparable to that afforded by the ischemia associated with the first balloon inflation in control subjects (early phase of ischemic PC). Collateral flow (estimated from a pressure-derived index) did not differ between control and NTG-pretreated patients, indicating that the enhanced tolerance to ischemia in NTG-pretreated patients cannot be accounted for by baseline differences in collateral function. CONCLUSIONS: NTG protects human myocardium against ischemia 24 hours after its administration. To the best of our knowledge, this is the first report that a late PC effect can be recruited pharmacologically in humans. The results suggest that prophylactic administration of nitrates could be a novel approach to the protection of the ischemic myocardium in patients.

Percutaneous transmyocardial laser revascularisation for severe angina: the PACIFIC randomised trial. Potential Class Improvement From Intramyocardial Channels.

BACKGROUND: Percutaneous transmyocardial laser revascularisation (PTMR) is a proposed catheter-based therapy for refractory angina pectoris when bypass surgery or angioplasty is not possible. We undertook a randomised trial to assess the safety and efficacy of this technique. METHODS: 221 patients with reversible ischaemia of Canadian Cardiovascular Society angina class III (61%) or IV (39%) and incomplete response to other therapies were recruited from 13 centres. Patients were randomly assigned PTMR with a holmium:YAG laser plus continued medical treatment (n=110) or continued medical treatment only (n=111). The primary endpoint was the exercise tolerance at 12 months. Analyses were by intention to treat. FINDINGS: 11 patients died and 19 withdrew; 92 PTMR-group and 99 medical-treatment-group patients completed the study. Exercise tolerance at 12 months had increased by a median of 89.0 s (IQR -15 to 183) with PTMR compared with 12.5 s (-67 to 125) with medical treatment only (p=0.008). On masked assessment, angina class was II or lower in 34.1% of PTMR patients compared with 13.0% of those medically treated. All indices of the Seattle angina questionnaire improved more with PTMR than with medical care only. By 12 months there had been eight deaths in the PTMR group and three in the medical treatment group, with similar survival in the two groups. INTERPRETATION: PTMR was associated with increased exercise tolerance time, low morbidity, lower angina scores assessed by masked reviewers, and improved quality of life. Although there is controversy about the mechanism of action, and the contribution of the placebo effect cannot be quantified, this unmasked study suggests that this palliative procedure provides some clinical benefits in the defined population of patients.

A comparison of directional atherectomy with coronary angioplasty in patients with coronary artery disease. The CAVEAT Study Group.

BACKGROUND: Directional coronary atherectomy is a new technique of coronary revascularization by which atherosclerotic plaque is excised and retrieved from target lesions. With respect to the rate of restenosis and clinical outcomes, it is not known how this procedure compares with balloon angioplasty, which relies on dilation of the plaque and vessel wall. We compared the rate of restenosis after angioplasty with that after atherectomy. METHODS: At 35 sites in the United States and Europe, 1012 patients were randomly assigned to either atherectomy (512 patients) or angioplasty (500 patients). The patients underwent coronary angiography at base line and again after six months; the paired angiograms were quantitatively assessed at one laboratory by investigators unaware of the treatment assignments. RESULTS: Stenosis was reduced to 50 percent or less more often with atherectomy than with angioplasty (89 percent vs. 80 percent; P < 0.001), and there was a greater immediate increase in vessel caliber (1.05 vs. 0.86 mm, P < 0.001). This was accompanied by a higher rate of early complications (11 percent vs. 5 percent, P < 0.001) and higher in-hospital costs ($11,904 vs $10,637; P = 0.006). At six months, the rate of restenosis was 50 percent for atherectomy and 57 percent for angioplasty (P = 0.06). However, the probability of death or myocardial infarction within six months was higher in the atherectomy group (8.6 percent vs. 4.6 percent, P = 0.007). CONCLUSIONS: Removing coronary artery plaque with atherectomy led to a larger luminal diameter and a small reduction in angiographic restenosis, the latter being confined largely to the proximal left anterior descending coronary artery. However, atherectomy led to a higher rate of early complications, increased cost, and no apparent clinical benefit after six months of follow-up.

Patient profile and follow-up in medically and surgically treated elderly adults with myocardial infarction.

We followed 23 elderly patients (age 75 years or older) with previous myocardial infarctions for an average of 22.4 months after cardiac catheterization. The mortality rate for the medically treated patients was 13%, and 28% for the surgically treated patients. Improvement in anginal symptoms over the follow-up period from the time of catheterization for the entire group was 50%. However, 100% of the surviving surgically treated patients were symptomatically improved with a mean improvement of 1.6 New York Heart Association functional class levels. The medically treated patients remained unchanged in their functional activity level. Catheterization mortality and morbidity were both zero in this group of 23 elderly patients.

Patient profile and follow-up in medically and surgically treated young adults with myocardial infarction.

Twenty-four young patients with myocardial infarction (average age 32.1 years) undergoing coronary arteriography after infarction were followed for an average of 33 months after catheterization. Prior inferior infarction was a predictor of two and three vessel coronary occlusive disease. Prior anterior infarction patients had a 64% incidence of single vessel coronary occlusive disease. Improvement in anginal symptoms over the follow-up period from the time of catheterization for the entire group was 69%. Employment at follow-up was excellent in both medically and surgically treated patients (80%). Cardiac mortality from the time of catheterization was extremely low (4%).

Body surface potential maps in patients with pulmonic valvular and aortic valvular stenosis of mild to moderate severity.

Multiple-lead surface potential maps were compared throughout ventricular activation in nine patients with mild-to-moderate pulmonic stenosis and in 12 patients with mild-to-moderate aortic stenosis. Abnormal patterns of potential distribution were found in aortic stenosis, including three patients without electrocardiographic evidence of left ventricular enlargement. When related to the onset of depolarization, abnormal departures started later, peaked later, lasted longer, and were more intense, more uniform and discrete in aortic stenosis. In pulmonic stenosis, abnormal departures started earlier, but were more dispersed in timing and location than in aortic stenosis. The left ventricle appears to be the more remote, though more powerful and compact, generator. The right ventricular shell, however, is nearer to the surface, and is more anatomically extended in surface area, permitting much wider shifts in wavefront location and orientation as a result of small differences in pressure, or volume, or location of the heart in the thorax.

Coronary atherosclerosis in valvular heart disease.

To evaluate the usefulness of routine coronary arteriography in patients undergoing cardiac catheterization for the evaluation of valvular heart disease, we performed coronary arteriographic studies routinely in a series of 201 patients primarily catheterized for such evaluation. Coronary artery obstructive lesions in excess of 50% of the lumen were present in 45 of the 201 patients. In 18 of the 45 there was no history of chest pain. Three of the 18 had three vessels involved while 2 had two vessels involved. A total of 27 patients (13.4%) had luminal obstruction greater than 70%, and 9 of these had no pain. In 35 of the 201 patients, classic angina pectoris existed in the absence of radiographically significant disease. Severe coronary disease was found to coexist with hemodynamically severe valvular heart disease and was not predictable noninvasively.

Effects of large doses of intravenous atropine on heart rate and arterial pressure of anesthetized patients.

A bolus of 3 mg. of atropine was given intravenously (I.V.) TO 123 ANESTHETIZED PATIENTS. Increases in heart rate were seen in 109 patients (88 percent), while 7 patients (5.7 percent) had no change. A mean increase in systolic arterial blood pressure of 14 mm. Hg was noted. A certain pattern in increases in heart rate and systolic blood pressure was observed. Ninety-six percent of the patients under cyclopropane, fluroxene, ether, ketamine, or regional (spinal or epidural) anesthesia had heart-rate increases, compared with only 77 to 89 percent of the patients anesthetized with halothane, enflurane, or neuroleptanalgesics. Rise in systolic blood pressure was seen in 40 to 50 percent of the former, but only in 31 to 40 percent of the latter group. The arrhythmias observed were transient A-V junctional tachycardias in three instances and bigeminal rhythm in one patient under cyclopropane anesthesia, The administration of a vagolytic dose of atropine to anesthetized patients appears not to be as arrhythmogenic as previously considered.

Exercise stress testing in patients with chest pain and normal coronary arteriography: with review of the literature.

Eighty of 654 patients studied because of chest pain were found to have normal coronary arteriography. Fifty of these completed submaximal treadmill exercise studies. The purpose of this study was to determine whether treadmill electrocardiography could obviate the need for coronary arteriography in the evaluation of patients with undiagnosed chest pain. Of patients studied, 22% had typical angina pectoris, while 78% had atypical chest pain. The resting electrocardiogram was normal in 58% of patients, while 42% showed repolarization abnormalities. Submaximal treadmill testing was normal in 64%, incomplete in 12%, and demonstrated classic ischemic S-T depression in 24%. Our findings of 24% positive studies in patients with normal vessels and 12% incomplete tests suggest that stress electrocardiography may be of limited value in predicting the morphologic state of the coronary arteries in patients with undiagnosed chest pain.