Dual antiplatelet therapy versus aspirin alone in patients undergoing transcatheter aortic valve implantation

Dual antiplatelet therapy (DAPT) with clopidogrel and aspirin is a widely accepted strategy in patients undergoing transcatheter aortic valve implantation (TAVI), but this approach is not evidence based. The goal of the present study was to determine whether DAPT in patients undergoing TAVI is associated with improved outcomes compared to aspirin alone. From May 2009 to August 2010, consecutive patients were randomized to receive a 300-mg loading dose of clopidogrel on the day before TAVI followed by a 3-month maintenance daily dose of 75 mg plus aspirin 100 mg lifelong (DAPT group) or aspirin 100 mg alone (ASA group). The primary end point was the composite of major adverse cardiac and cerebrovascular events, defined as death from any cause, myocardial infarction, major stroke, urgent or emergency conversion to surgery, or life-threatening bleeding. The cumulative incidence of major adverse cardiac and cerebrovascular events at 30 days and 6 months was 14% and 16%, respectively. No significant differences between the DAPT and ASA groups were noted at both 30 days (13% vs 15%, p = 0.71) and 6 months (18% vs 15%; p = 0.85). In conclusion, the strategy of adding clopidogrel to aspirin for 3 months after TAVI was not found to be superior to aspirin alone. These results must be confirmed in a larger randomized trial.

Transcatheter aortic valve implantation for severe aortic regurgitation in a stentless bioprosthetic valve with the Core Valve revalving system-technical tips and role of the Accutrak system

Transcatheter aortic valve implantation may offer a less invasive alternate to surgical reoperation in patients with failed aortic bioprosthetic valves. Prior reports have focussed on successful transcatheter treatment of stented bioprosthesis. Newer stentless valves offer unique technical challenges. In the absence of radiopaque markers, the deployment is carried out under angiographic control. Device stability is also an important issue in cases of severe regurgitation. We report on the first case of percutaneous replacement of a severely regurgitant degenerated stentless bioprosthesis treated with the new iteration of the core valve system incorporating the Accutrak stability layer. Salient technical expedients have been mentioned and discussed in detail.

A randomized pilot trial for aggressive therapeutic approaches in aspirin-resistant patients undergoing percutaneous coronary intervention

BACKGROUND

There is great variability among individual patients in platelet inhibition after aspirin intake. Aspirin resistance has been associated with a higher incidence of ischemic events after percutaneous coronary intervention (PCI). The optimal antiplatelet therapy in aspirin-resistant patients undergoing PCI is unknown. The objective of this study was to evaluate whether aggressive antiplatelet therapy would reduce ischemic events in aspirin-resistant patients after PCI.

METHODS

A total of 330 patients undergoing PCI (with bivalirudin) were screened for aspirin responsiveness. The resulting 36 aspirin-resistant patients were randomized into two arms: 1) conventional strategy patients received 325 mg aspirin orally and a loading dose of 600 mg clopidogrel at the time of the procedure; and 2) aggressive strategy patients received similar amounts of aspirin and clopidogrel, with the addition of an intravenous glycoprotein IIb/IIIa inhibitor bolus intraprocedurally. The primary outcome was an elevation of cardiac enzymes within 24 hours post procedure. The secondary outcome was a composite of major adverse cardiac events including death, myocardial infarction, stent thrombosis and urgent revascularization, and bleeding up to 30 days.

RESULTS

Primary outcome occurred in 22% of the conventional strategy group and 11% of the aggressive strategy group (p = 0.36). The secondary outcome was reached in 27.8% of the conventional group and 5.5% of the aggressive strategy group (p = 0.17), which is suggestive of a statistical trend toward more ischemic events with conventional therapy. Importantly, there were 2 cases of definite stent thrombosis in the conventional strategy group.

CONCLUSION

In aspirin-resistant patients, aggressive antiplatelet therapy tended to show better outcomes after PCI, without an increase in bleeding. These findings need validation in a large, randomized study.

Catheter selection for coronary angiography and intervention in anomalous right coronary arteries

BACKGROUND

An anomalous origin of the right coronary artery (ARCA) from the left sinus of Valsalva (LSOV) has been reported in 6-27% of patients with coronary anomalies. The unusual location and course of this anomaly poses a technical challenge for the interventionalist. Appropriate guiding catheter selection is critical to ensure successful angiography and percutaneous intervention (PCI). We report our experience in 24 patients with an anomalous RCA originating from the LSOV.

METHODS

Twenty-four angiograms of ARCA-LSOV were reviewed by two independent interventionalists with attention to the origin and take off of the RCA within the aortic root. The origin was adjudicated with a scheme based on anatomical landmarks as described-A: origin from the aorta above the sinotubular plane; B: origin just below the ostium of the left coronary artery (LCA); C: origin below the sinotubular plane between the midline and the LCA; D: origin along the midline.

RESULTS

The distribution of various takeoffs of the RCA was as follows: For type A (N = 4) the FL3.0 and FCL3.0 catheters were successful in three and one cases, respectively. For type B (N = 5) the FCL3.0 or 3.5 was successful in four out of the five cases. For type C (N = 9) the VL catheter was successful in eight (VL3.5 = 5:VL 3.0 = 3) cases. The AL catheter was successful in five cases of type D (N = 6) RCAs (AL1 = 3:AL2 = 1:AL3 = 1).

CONCLUSIONS

The classification method and catheter selection provide a useful framework to successfully engage ARCA-LSOV and may reduce contrast and radiation exposure.

Revascularization of chronic total occlusion of coronary artery: a challenge and an opportunity

Remarkable progress has been achieved in the percutaneous management of coronary artery disease over the last decade. In the early 1990s, the primary success rate with the use of bare metal stents was 86-88% and the restenosis rate, 30%-40%. Over the last decade, drug-eluting stents have been developed to check the high rates of in-stent restenosis following percutaneous coronary revascularization. In randomized trials, polymer-coated sirolimus- and paclitaxel-eluting stents, when compared to bare metal stents, have been shown to markedly reduce the incidence of both angiographic restenosis and repeat revascularization. The effectiveness of drug-eluting stents in the prevention of restenosis has been confirmed in patients with stable stenotic lesions, as well as many patients with specific lesions, such as those with in-stent restenosis and acute myocardial infarction. Currently, the primary success rate using drugeluting stents has risen to over 95% and the restenosis rate to less than 10%. In spite of remarkable technological advances and improved outcomes with percutaneous coronary revascularization, chronic total occlusions of the coronary artery remain a source of procedural frustration and clinical uncertainty. With continued developments in catheterbased technologies, there is an opportunity to achieve recanalization of chronic total occlusions with drug-eluting stents; this subset of patients is now recognized as the last formidable barrier to the success of percutaneous revascularization. This review provides an overview of the pathophysiology of chronic total occlusions and the clinical outcomes associated with chronic total occlusion revascularization, and provides future directions for clinical investigation.

Coronary artery restenosis: vascular biology and emerging therapeutic strategies

Percutaneous coronary intervention with drug-eluting stents is currently the preferred approach to the treatment of obstructive coronary stenoses. Large, randomized trials have demonstrated a significant reduction in the incidence of restenosis after drug-eluting stent placement compared with balloon angioplasty or bare metal stents across a wide range of lesions. Furthermore, these stents have appeared to be effective in maintaining the luminal patency at follow up for up to 2-4 years. Concerns regarding the potential adverse effects of drug-eluting stents, such as aneurysm formation in arteries secondary to drug toxicity or hypersensitivity, as well as the overdependence on antiplatelet therapy for a protracted period to prevent subacute thrombosis, have been raised. However, evidence from large studies has not demonstrated any significant increase in the incidence of such adverse events. Future approaches to treating coronary stenoses involve technical modifications, such as direct stenting, accelerating endothelialization with gene delivery of nitric oxide donors, smooth muscle cell growth inhibitors after stent placement, biodegradable stents and concurrent use of local molecule delivery and oral chemotherapy. Ongoing large-scale postmarketing surveillance studies are expected to provide credible answers to the concerns regarding the safety of these stents.

The role of statins in endothelial dysfunction in hypertension

PURPOSE OF REVIEW

Hypertension and dyslipidemia frequently coexist, and endothelial dysfunction is associated with the pathophysiology of both atherosclerosis and hypertension. Evidence is convincing for an overlapping role of oxidative stress, renin-angiotensin system activation, and dyslipidemia in the genesis of endothelial dysfunction.

RECENT FINDINGS

Ample experimental and human data suggest that common cellular pathways are involved in the pathogenesis of hypertension, increased vascular resistance, and plaque formation. Multiple interventions such as dietary modification, exercise, antioxidants, and antihypertensive drugs improve endothelial dysfunction in hypertension. Statin drugs are a cornerstone of dyslipidemia therapy. Studies have demonstrated that statins correct endothelial function and vascular stiffening and may be useful in reducing blood pressure to target levels.

SUMMARY

Statins may be a useful adjunct in the treatment of hypertension in patients with dyslipidemia and possibly those with normal cholesterol levels.

Epidemiology of HIV infection among brothel-based sex workers in Kolkata, India

A cross-sectional study was carried out during January-June 2004 to assess the status of HIV infection among brothel-based sex workers in Kolkata city, India. Six hundred and twenty-two sex workers, selected from six brothels, were included in the study to assess their HIV status, and 362 sex workers, a subset of the above population, were interviewed to study their risk behaviour and practices. Blood samples were collected from each sex worker for testing HIV by an unlinked anonymous method. The prevalence of HIV infection was 9.6%, but was much higher among younger sex workers aged 20 years or less (27.7%) compared to the older age group (8.4%). This difference was statistically significant, indicating an association of younger ages with HIV infection [p = 0.006 and odds ratio (OR) = 4.18; (95% confidence interval (CI) 1.2-13.8)]. HIV was not associated with duration of sex work, average number of clients entertained per day, condom use, practice of sex during menstruation, pre-coital examination of penis for visible ulcer/discharge, suffering from sexually transmitted infections, and entertaining clients outside the brothel. There was a big gap between the reported and the evaluated condom use by sex workers. The results suggest that there is a need to develop suitable HIV intervention strategies, considering the socioeconomic and cultural aspects of city sex workers, with a provision for continuous monitoring and evaluation.