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Biomedical subjects

M R Rinder

Publications and source records attributed to M R Rinder.

9 recordsLinked to original sources

Safety and efficacy of suture-mediated closure after percutaneous coronary interventions.

Percutaneous coronary interventions (PCI) performed with concomitant use of heparin and platelet inhibitors are safe procedures with reported vascular complication rates of approximately 6.1%. EPILOG investigators demonstrated that utilizing a low-dose heparin regimen with abciximab, along with early sheath removal, vascular access-related bleeding was significantly lower than that reported in EPIC. Recently, a suture-mediated closure (SMC) device has been reported to be safe, appears effective, and may improve patient comfort by allowing early ambulation. We conducted a retrospective analysis (January 1999 to March 2000) of complication frequencies among PCI patients who underwent SMC and those who had manual compression (non-SMC). Furthermore, we compared the overall rates of complications to patients who underwent PCI prior to the introduction of SMC (1995-1998). When comparing the current cohort to the historical cohort, there was a significant decrease in the number of retroperitoneal bleeds (0.3% vs. 0.9%; P = 0.003), hematomas (5% vs. 9%; P < 0.001), pseudoaneurysms (1.2% vs. 2.7%; P < 0.001), and need for vascular surgery (0.9% vs. 2.8%; P < 0.001). There was no difference in the number of arterio-venous fistulas and a slight increase in transfusion needs (12% vs. 10%; P = 0.03). Within the current cohort, there was no difference in the vascular complications between SMC and non-SMC PCI patients, although there were lower rates of pseudoaneurysms (0.5% vs. 1.8%; P = 0.02) and transfusion requirements (72/880 vs. 132/874; P < 0.001). These results suggest that the complication rates for SMC are not different and may be lower when compared to non-SMC patients after PCI. At our institution, the practice of early sheath removal and less aggressive heparin dosing has led to a decrease in vascular complication rates and a 66% reduction in vascular surgeries on post-PCI patients. Because of the limitations of retrospective analyses, further studies will be necessary to confirm these findings.

Aged↗

Enhanced inotropic response to dobutamine in strength-trained subjects with left ventricular hypertrophy.

To determine whether strength-trained individuals with physiological concentric left ventricular (LV) hypertrophy exhibit enhanced inotropic responses to catecholamines, we studied 11 bodybuilders, aged 33.0 +/- 2 (SE) yr old, and 10 sedentary healthy subjects, aged 31.3 +/- 2.4 yr old, at baseline and during infusion of incremental doses of dobutamine after atropine. The bodybuilders had larger LV mass, posterior wall and septal wall thicknesses, and wall thickness-to-radius ratio, assessed with two-dimensional echocardiography, than did the sedentary subjects. There was a significant correlation between LV mass and lean body mass irrespective of training status. Baseline LV fractional shortening was similar in the two groups. There was a greater inotropic response to dobutamine in the strength-trained individuals, as evidenced by a steeper slope of the fractional shortening-end-systolic wall stress relationship with a higher y-axis intercept and by a shallower end-systolic wall stress-end systolic diameter relationship without changes in end-diastolic diameter. The heart rate response to dobutamine was attenuated in the strength-trained athletes. There was a significant correlation (r = 0.604, P < 0.05) between the inotropic sensitivity to dobutamine and LV mass normalized for lean body mass in the bodybuilders. The data suggest that concentric LV physiological hypertrophy in the resistance-trained individuals is associated with enhanced inotropic but not chronotropic responses to catecholamines.

Adrenergic beta-Agonists↗

Enhanced endothelium-dependent vasodilation in older endurance-trained men.

We hypothesized that abnormal endothelium-dependent vasodilation (EDD) found in older otherwise healthy subjects can be attenuated with long-term endurance training. Ten endurance-trained men, 68.5 +/- 2.3 yr old, and 10 healthy sedentary men, 64.7 +/- 1.4 yr old, were studied. Aerobic exercise capacity (VO(2 max)), fasting plasma cholesterol, insulin, and homocysteine concentrations were measured. Master athletes had higher VO(2 max) (42 +/- 2.3 vs. 27 +/- 1.4 ml. kg(-1). min(-1), P < 0.001), slightly higher total cholesterol (226 +/- 8 vs. 199 +/- 8 mg/dl, P = 0.05), similar insulin, and higher homocysteine (10.7 +/- 1.3 vs. 9.2 +/- 1.4 micromol/ml, p = 0.02) concentrations. Brachial arterial diameter, determined with vascular ultrasound, during the hyperemic response was greater in the master athletes than in controls (P = 0.005). Peak vasodilatory response was 109.1 +/- 2 vs. 103.6 +/- 2% (P < 0.05) in the athletes and controls, respectively. Endothelium-independent vasodilation in response to nitroglycerin was similar between the two groups. The increased arterial diameter during the hyperemic response correlated significantly with the VO(2 max) in the entire population (r = 0.66, P < 0.002). Our results suggest that long-term endurance exercise training in older men is associated with systemic enhanced EDD, which is even detectable in the conduit arteries of untrained muscle.

Aged↗

Effects of endurance exercise training on left ventricular systolic performance and ventriculoarterial coupling in patients with coronary artery disease.

BACKGROUND: Endurance exercise training can increase left ventricular (LV) ejection fraction during dynamic exercise in coronary artery disease. This adaptation may be mediated by altered cardiac loading conditions rather than an improvement in intrinsic LV systolic function. To minimize these confounding effects, we used isometric handgrip exercise to assess the training-induced changes in LV systolic function and ventriculoarterial coupling. METHODS: Twenty-six patients (52 +/- 2 years of age) trained for 12 months. LV function was assessed with radionuclide ventriculograpy. RESULTS: LV systolic reserve (the change in LV ejection fraction from rest to handgrip exercise) increased from -7.32 +/- 1.2 to -3.4 +/- 1.1 (P =. 033) without acute changes in end-diastolic volume or the effective arterial load. LV end-systolic elastance increased 37% (P =.039) during handgrip exercise. Resting end-diastolic volume increased and the effective arterial load decreased after training. CONCLUSIONS: Data suggest that in coronary artery disease adaptations to exercise training include a lower effective arterial load and an increase in EDV at rest, with an improvement in LV systolic function detectable only during afterload stress.

Arteries↗

Acquired von Willebrand's disease: a concise review.

Acquired von Willebrand's disease (AvWD), an adult-onset bleeding diathesis, has most commonly been found in patients with an underlying lymphoproliferative disease or monoclonal gammopathy. Other malignancies, autoimmune diseases, hypothyroidism, and drugs have also been associated with AvWD. We have included an illustrative case history of a patient with a bleeding diathesis consistent with AvWD and a monoclonal gammopathy who required emergent cardiac surgery. Our review of the literature determined that most cases of AvWD are due to a circulating antibody that combines with the high molecular weight multimers (HMWM) of von Willebrand factor (vWF). These vWF multimer-antibody complexes are subsequently cleared from the circulation either by the reticuloendothelial system or by adsorption onto tumor cells. Clearance of the HMWM of vWF thus results in extremely low functional levels and variable antigenic levels. Mixing studies which are traditionally used to diagnose factor inhibitors are useful only if removal of vWF-antibody complexes can be accomplished in vitro. Treatment with intravenous immunoglobulin has recently been shown to be the most effective therapy for patients with an underlying lymphoproliferative disorder or monoclonal gammopathy. This therapeutic strategy is based on the observed immune complex clearance phenomenon that appears to be operative in most cases. Other AvWD-associated diseases require treatment specifically directed at the underlying disorder.

Antibodies↗

Renal abscess: an illustrative case and review of the literature.

A patient had pyleonephritis with fever and pain that did not resolve, which prompted an abdominal ultrasound examination that showed an abscess within the renal cortex. Renal abscesses are particularly dangerous because of their location and potential spread to adjacent tissues. Although ultrasound is the best modality for imaging a renal abscess, computed tomography provides better tissue contrast, especially in obese patients. The pathophysiology of renal abscesses has changed during the past 25 years. Most cases are now caused by gram negative enteric organisms that are similarly pathogenic in uncomplicated cystitis and pyelonephritis. Successful treatment of a renal abscess requires long-term intravenous and oral antibiotics; surgical or percutaneous drainage is reserved for nonresponders.

Abscess↗