2 Minute Medicine Rewind November 18-24, 2013

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In this section, we will highlight the key high-impact studies, updates, and analyses published in medicine during the past week. This past week, the AHA had its annual meeting and a variety of cardiovascular health results were announced and described.

Mitral-Valve Repair versus Replacement for Severe Ischemic Mitral Regurgitation

Mitral valve regurgitation after myocardial infarction is thought to be due to left ventricular remodeling and is associated with significant mortality; however there is limited data on the optimal surgical management. Mitral valve repair also has less peri-operative morbidity – however mitral valve replacement is thought to have some potential long term benefits in efficacy. In this multicenter trial, 251 participants screened from 3458 patients were randomized 1:1 to mitral valve repair or mitral valve replacement. At one year, there was no significant difference in cumulative mortality with a trend towards less mortality in the repair arm (HR 0.79, 95% CI, 0.42 to 1.47, p = 0.45 by the log-rank test). Also at one year, there was no significant difference in major adverse cardiac or cerebrovascular events (hazard ratio, 0.91; 95% CI, 0.58 to 1.42; P=0.68 by the log-rank test). For the repair arm, there was a 30% increase in moderate or severe mitral valve regurgitation however no differences in quality of life or functional status at one year. Further study should be undertaken to assess the long term benefits and risks of the surgical management of mitral valve regurgitation.

Targeted Temperature Management at 33°C versus 36°C after Cardiac Arrest

Therapeutic hypothermia has been used for potential neuroprotective benefits in the setting of unconscious patients after resuscitation from cardiac arrest. In this multicenter randomized controlled trial, 950 patients arriving to the hospital unconscious from presumptive cardiac cause were randomized to targeted temperature management to 33°C or 36°C. At 180 days, there was no significant difference in cumulative mortality between the two groups (50% at 33°C 48% at 36°C, risk ratio 1.02; 95% CI, 0.88 to 1.16; P=0.78). Death or poor neurological function measured by Cerebral Performance Category or modified Rankin scale were similar for both groups. In unconscious survivors of out-of-hospital cardiac arrest of presumed cardiac cause, hypothermia at a targeted temperature of 33°C did not confer a benefit as compared with a targeted temperature of 36°C.

Comparative Safety of Vascular Closure Devices and Manual Closure Among Patients Having Percutaneous Coronary Intervention

Vascular closure devices have been used after percutaneous intervention to minimize femoral bleeds, hematomas, and other vascular complications however recommendations for their use varies and is still controversial. In this observational cohort study, investigators examined 85,048 percutaneous interventions and assessed the need for post-procedure transfusions and rate of vascular complications. Of the 85,048 procedures, 28,528 procedures used vascular closure devices and these procedures were associated with fewer vascular complications (OR 0.78, [95% CI, 0.67 to 0.90]; P = 0.001) and post-procedure transfusions (OR 0.85, [CI, 0.74 to 0.96]; P = 0.011). There was less of a benefit in patients with Body Mass Index less than 25 and patients treated with platelet glycoprotein (GP) IIb/IIIa inhibitors.

Outcomes Following Transcatheter Aortic Valve Replacement in the United States

Transcatheter Aortic Valve Replacement (TAVR) has been approved to the treatment of symptomatic severe aortic stenosis in inoperable and high-risk patients since November 2011. This retrospective cohort analysis describes the outcomes of 7710 TAVR procedures performed at 224 US centers from a national registry of all TAVR procedures in the US since November 2011. Of the 7710 patients, 1559 (20%) were deemed inoperable and 6151 (80%) were high-risk candidates with a median age of 84 and median STS predicted 30-day mortality of 7%. There was a 5.5% in-hospital mortality rate, 7.6% 30-day mortality rate, and 2.8% 30-day stroke rate. Device implantation success occurred in 92% of cases, with 0.5% requiring re-intervention.

Cessation of dual antiplatelet treatment and cardiac events after percutaneous coronary intervention (PARIS): 2 year results from a prospective observational study

Patients are prescribed dual antiplatelet therapy (DAPT) after percutanous intervention with stenting and cessation of DAPT has been associated with increased risk of in-stent thrombosis. In this international multicenter prospective observational study of 5031 patients undergoing PCI with stent placement, patients were surveyed to track if they stopped DAPT, the reason for stopping, and the rates of major adverse cardiac events (MACE: cardiac death, stent thrombosis, myocardial infarction, or target lesion revascularization). Over two years, the overall incidence of DAPT discontinuation was 57.3%. 10.5% of interruptions were brief interruptions for surgery and 14.4% were disruptions due to non-compliance or bleeding. The overall MACE rate was 11.5%, of which the majority (74%) occurred in patients while on DAPT. The HR of MACE due to DAPT interruptions was 1.41 (95% CI 0.94 – 2.12, p = 0.10) and disruptions was 1.50 (95% CI 1.14 – 1.97, p = 0.004). Patients undergoing PCI with stenting have significant risk of MACE with or without DAPT, however the early risk is higher without DAPT.

Association of Nut Consumption with Total and Cause-Specific Mortality

Nut consumption has been associated with reduced cardiovascular risk and decreased risk of type 2 diabetes mellitus. In this retrospective analysis of women in the Nurse’s Health Study (1980 – 2010) and men in the Health Professionals Follow-up Study (1986 -2010), investigators looked at the recorded consumption of nuts and correlated its effect on cardiovascular related mortality and all-cause mortality. All-cause mortality was found to inversely trend with nut consumption (P < 0.001 for trend) with a HR of 0.80 (95% CI 0.73-0.86) for participants who consumed nuts 7 or more times per week compared to participants who did not consume nuts. This inverse correlation was found for both men and women as well as for deaths related to cancer, heart disease, and respiratory disease. This research was funded by the International Tree Nut Council Nutrition Research and Education Foundation.

By David Ouyang

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