Development of collateral circulation after acute myocardial infarction: its role in preserving left ventricular function

The present study evaluated the effects of coronary collateral circulation developing after acute myocardial infarction on global and regional left ventricular function during the chronic stage. The study group consisted of 16 patients with initial myocardial infarction having total occlusion of the proximal left anterior descending coronary artery. To eliminate the effects of collateral circulation existing at the onset of infarction, patients with pre-infarction angina were excluded from this study. The patients were categorized in two groups depending on the extent of their collateral circulation (collateral index: CI 0-3): group A--patients with significant collateral circulation (CI = 2 or 3) to the infarct-related coronary artery; group B--patients without significant collateral circulation (CI = 0 or 1). Their heart rate, left ventricular peak systolic and end-diastolic pressures and cardiac index were similar in the two groups. The left ventricular end-systolic volume index in the group B was significantly greater than that in the group A (60 +/- 21 ml/m2 vs 34 +/- 9 ml/m2, p less than 0.05). Left ventricular ejection fraction in the group A was significantly greater than that of the group B (55 +/- 9% vs 39 +/- 15%, p less than 0.05), and a significant difference was observed in the percentage of segment shortening in the infarct area between the groups A and B (10.8 +/- 9.2% vs -0.2 +/- 5.4%, p less than 0.01). It was concluded that coronary collateral circulation which develops after acute myocardial infarction exerts beneficial effects on global and regional left ventricular function during the chronic stage.     

Sodium/calcium exchange modulates intracellular calcium overload during posthypoxic reoxygenation in mammalian working myocardium. Evidence from aequorin-loaded ferret ventricular muscles.

We tested the hypothesis that the intracellular Ca2+ overload of ventricular myocardium during the period of posthypoxic reoxygenation is mediated by transsarcolemmal Ca2+ influx via Na+/Ca2+ exchange. In aequorin-loaded, ferret right ventricular papillary muscles, blockers of the sarcolemmal and the sarcoplasmic reticulum Ca2+ channels, slowed the Cai2+ transient, producing a convex ascent during membrane depolarization, followed by a concave descent during repolarization. The magnitude of the Cai2+ transient was affected by changes in the membrane potential, Nai+, Nao+, and Cao2+, and was blocked by Ni2+, or dichlorbenzamil. The calculated Na+/Ca2+ exchange current was in the reverse mode (Ca2+ influx) during the ascending phase of the Cai2+ transient, and was abruptly switched to the forward mode (Ca2+ efflux) at repolarization, matching the time course of the Cai2+ transient. During hypoxic superfusion, the Cai2+ transient was abbreviated, which was associated with a shorter action potential duration. In contrast, immediately after reoxygenation, the Cai2+ transient increased to a level greater than that of the control, even though the action potential remained abbreviated. This is the first demonstration on a beat-to-beat basis that, during reoxygenation, Ca2+ influx via Na+/Ca2+ exchange is augmented and transports a significant amount of Ca2+ into the ventricular myocardial cell. The activation of the exchanger at the time of reoxygenation appears to be mediated by Nai+ accumulation, which occurs during hypoxia.     

The effect of hydrocortisone on reducing rates of restenosis and target lesion revascularization after coronary stenting less than 3 mm in stent diameter

OBJECTIVE: Stenting of small coronary arteries has always been limited by high rates of restenosis, and restenosis has mainly been attributed to inflammatory reactions resulting in cell proliferation and intimal hyperplasia. Based on our experience for several years, we retrospectively investigated the effect of hydrocortisone on reducing in-stent restenosis. PATIENTS AND METHODS: Study population consisted of consecutive 166 patients, 221 lesions, who electively underwent stent implantations stent diameter less than 3 mm into coronary arteries between February 1999 and October 2002. We intravenously administered hydrocortisone before the procedure to 40 patients for preventing allergic reactions due to contrast material, and the effect of hydrocortisone on reducing restenosis was retrospectively compared with 126 patients who did not receive this treatment. RESULTS: There was no significant difference in the prevalence of diabetes mellitus, hyperlipidemia, or hypertension between the two groups. There was no significant difference in the type of lesion, length of stent, balloon/artery ratio, or initial success rate between the two groups, but stent diameter was significantly smaller in the hydrocortisone group compared with the control group. On six-month angiographic follow-up, the restenosis rate was significantly lower in the hydrocortisone group compared with the control group (16.2% vs 34.0%, respectively), and the target lesion revascularization rate was also significantly lower in the hydrocortisone group compared with the control group (13.2% vs 27.5%, respectively). CONCLUSION: These results suggest that intravenous administration of hydrocortisone reduces in-stent restenosis of small coronary arteries. Prospectively controlled trials will be necessary to confirm this preventive effect of hydrocortisone.     

Age-dependent impairment of coronary collateral development in humans

The purpose of this study was to evaluate whether age influences collateral development in patients with coronary artery disease. The extent of collateral development to the area perfused by the infarct-related artery was graded, depending on the degree of opacification of the occluded infarct-related artery. We evaluated the extent of collateral development using coronary cineangiography in 102 patients with an acutely occluded infarct-related coronary artery within 12 h after the onset of the first acute myocardial infarction, and who had a history of long-standing effort angina. Well-developed collateral circulation was observed in 54 (53%) of the patients. The patients were divided into two groups based on their age. The prevalence of well-developed collateral circulation in the younger group (≤64 years, n = 48) was 69% (33 of 48), being significantly (P = 0.003) higher than 39% (21 of 54) in the older group (≥65 years, n = 54). We conclude that in the presence of stimuli for collateral development i.e., long-standing effort angina accompanied by severe coronary stenosis, the age of patients is a key determinant of collateral development. Received: September 30, 2000 / Accepted: January 12, 2001     

Prognostic effects of combined treatment with calcium channel blockers and statins in patients with coronary narrowing: from the Japanese Coronary Artery Disease study

Calcium channel blockers (CCB) and statins are frequently prescribed for patients with coronary artery disease (CAD) complicated by hypertension and/or hypercholesterolemia. CCB have pleiotropic actions beyond their blood pressure-lowering effect, while statins have pleiotropic actions beyond their cholesterol-lowering effect. We assessed the hypothesis that combined treatment with CCB and statins has additional prognostic benefits resulting from potential additive or synergistic pleiotropic actions of both classes of drugs in the Japanese CAD (JCAD) study population. The JCAD study consisted of 13,812 patients with angiographically demonstrable significant coronary narrowing in at least 1 of 3 major coronary arteries who were followed-up for a mean of 2.7 years (follow-up rate, 88.4%). The primary endpoint of the present study was all cardiovascular events. We compared the event rate between patients receiving neither CCB nor statins and those receiving each drug alone or as a combination treatment using propensity score matching analysis. The rate of all events was 62.8 per 1,000 patient-years in the JCAD study. Kaplan-Meier analysis with the log-rank test showed no statistically significant difference in the event rate in each comparison. In conclusion, there may be no additional prognostic benefit beyond the blood-pressure-lowering and cholesterol-lowering effects in the combined treatment with CCB and statins for angiographically documented CAD patients.     

Rapid regrowth of an atypical choroid plexus papilloma located in the cerebellopontine angle

Choroid plexus papilloma usually occurs in the lateral or the fourth ventricle. Primary choroid plexus papilloma of the cerebellopontine angle, as described here, is an uncommon lesion. A 42-year-old man presented with a 1-month history of dysphagia and gait unsteadiness. CT scans and MRI showed a large extra-axial tumor in the right cerebellopontine angle. Pathological study revealed that the lesion was choroid plexus papilloma. Repeat imaging conducted 1 year after the operation showed that the tumor had recurred with distinct cystic features. Pathological examination again revealed increased mitotic activity and supported a diagnosis of atypical choroid plexus papilloma.     

Intercostal nerve cross-anastomosis and DREZ-tomy in a patient with brachial plexus avulsion

An 18-year-old male with a right brachial plexus injury caused by a motorcycle accident was admitted on October 13, 1988. A detailed examination revealed that the brachial plexus was totally injured. The axon reflex test suggested that the lesion sites were postganglionic in the C5 and C6 nerves, and preganglionic in the C7, C8 and Th1. On December 14, 1988, intercostal nerve cross-anastomosis was performed in the hope that a lost motor function of the right upper extremity could be restored as a first step. An electromyogram 6 months after this anastomotic operation demonstrated synkinesis between the biceps brachialis and the intercostal muscles during deep inspiration. Fifteen months after this operation, active voluntary muscle discharges which were higher than before in amplitude, were provoked. The right elbow flexion was gradually restored independently of respiration. On the other hand, intractable pain with a persistent severe tingling sensation appeared approximately one week after the injury on the lesioned upper extremity. The pain rapidly increased in severity. The DREZ-tomy from C5 to Th1 was performed on March 7, 1989. This has brought complete relief of the intractable pain. A brief discussion was given concerning some aspects of the brachial plexus avulsion and DREZ-tomy.