Anwar Tandar

Endovascular therapy for acute ischaemic stroke: a systematic review and meta-analysis of randomized trials

AIMS Evidence from randomized controlled trials (RCTs) evaluating possible benefits of endovascular therapy (EVT) for acute ischaemic stroke has shown conflicting results. The purpose of this meta-analysis was to systematically examine clinical outcomes in RCTs comparing the use of intravenous (IV) fibrinolysis alone to IV fibrinolysis plus EVT, for the treatment of acute ischaemic stroke. METHODS AND RESULTS We selected English language RCTs, comparing EVT plus IV tissue-type plasminogen activator (tPA) (if eligible) with IV tPA alone in eligible patients for the treatment of acute ischaemic stroke. The primary endpoint was good functional outcome [modified Rankin Scale (mRS) of 0-2]. Other major endpoints of interest were all-cause mortality and symptomatic intracerebral haemorrhage (sICH). The meta-analysis included 8 RCTs that randomized 2423 patients with large-vessel, anterior-circulation stroke. EVT significantly improved the rate of functional independence (90-day mRS of 0-2) when compared with IV fibrinolysis [odds ratio (OR) 1.73, 95% confidence interval (CI) 1.18-2.53, number needed to treat (NNT) = 9.3]. The all-cause mortality was lower with EVT compared with the control group; however, the result did not reach statistical significance (OR 0.89, 95% CI 0.68-1.15). The rate of sICH was not higher with EVT (OR 1.07, 95% CI 0.73-1.56). Analyses from only the recent trials (reported in 2014-15) showed further benefit (OR of mRS 0-2: 2.42, 95% CI 1.91-3.08, NNT = 5) with similar safety results. CONCLUSION In centres with advanced systems of stroke care, EVT significantly improved functional outcomes (without compromising safety) in patients with acute ischaemic stroke due to anterior circulation, large artery occlusion, compared with standard therapy.

Stent fracture following stenting of a myocardial bridge: Report of two cases

Myocardial bridge is the most common congenital coronary anomaly. Patients with this anomaly are usually asymptomatic, but it may cause myocardial ischemia that may lead to myocardial infarction. Treatment for myocardial bridge remains controversial. Current recommendations include medical therapy, surgical treatment (unroofing myotomy), coronary artery bypass, and percutaneous coronary stenting. We report two cases of stent fracture following stenting of a myocardial bridge. The risk of stent fracture leading to restenosis and/or stent thrombosis should be considered when assessing the risks and benefits of coronary revascularization of a myocardial bridge.

Emerging medical treatment for angina pectoris

Importance of the field: Despite improved mortality and morbidity in the treatment of coronary artery disease, a significant proportion of patients will continue to experience recurrent angina pectoris. Areas covered in this review: Anti-anginal therapy has long been dominated by the use of β-blockers, Ca2+ channel blockers and nitrates. Most recently, ranolazine was introduced as a new anti-anginal class. This review article presents current and novel anti-anginal strategies under development. A discussion of their molecular mechanisms that may complement traditional therapies is presented. Medline and PubMed scientific search tools were primarily used to identify relevant literature dating from 1970 to 2008. What the reader will gain: This review provides a summary of both traditional and emerging therapeutic approaches to angina pectoris management. A discussion on the mechanism of action and clinical efficacy of ranolazine, trimetazidine, nicorandil, ivabradine, fasudil and growth factor gene therapy as anti-anginal agents is provided. Take home message: The need for multiple approaches cannot be over-emphasized. Availability of various modalities would strongly enhance the ability to meet the needs of a heterogeneous patient population. Patients with recurrent angina pectoris most likely will require multi-drug regimen where different mechanisms may complement each other and result in a more efficacious strategy.

Multiple left ventricular diverticuli in an asymptomatic adult: Case report and review of the literature

Left ventricular (LV) diverticulum is a rare congenital abnormality for which the etiology, management, and natural history are very poorly understood. Although most often observed as a single diverticulum, we report a case of multiple LV diverticuli in an asymptomatic adult referred for coronary evaluation due to an abnormal electrocardiogram. LV diverticuli are often associated with other congenital malformations, but can also be found in isolation. Cardiac magnetic resonance imaging provides enhanced ability to determine size, location, and morphological characteristics, which may improve lesion assessment and management. A review of the condition and reported complications is discussed.

Valve thrombosis following transcatheter aortic valve replacement: significance of blood stasis on the leaflets

OBJECTIVES Leaflet thrombosis following transcatheter aortic valve replacement (TAVR) and valve-in-valve (ViV) procedures has been increasingly recognized. However, the factors affecting the post-TAVR/ViV thrombosis are not fully understood. This study aimed to investigate the effect of the geometric confinement of transcatheter aortic valve (TAV) on blood residence time (BRT) on the TAV leaflets and in turn on the post-TAVR valve thrombosis. METHODS Two computational models, representing a surgical bioprosthesis and a TAV, were developed to study the effect of the geometric confinement on BRT on the leaflets in ViV setting/TAVR Intra-annular positioning. 3D flow fields were obtained via a one-way fluid-solid interaction modelling approach validated by experimental testing. BRT was compared between the two models by quantification and statistical analysis of the residence time of randomly distributed particles in close proximity of the leaflets. RESULTS Significantly longer BRT on the leaflets was observed in the TAV compared to the surgical valve during different stages of the cardiac cycle. During forward flow, the mean value of BRT was found to be 39% higher in the TAV compared to the surgical bioprosthesis ( P <  0.0001). During diastole, specifically from end-systole to mid-diastole and from mid-diastole to the beginning of systole, the amount by which the mean BRT was higher for TAV compared to the surgical valve was 150% and 40%, respectively ( P <  0.0005). CONCLUSIONS The geometric confinement of TAV by the failed bioprosthesis or the calcified native valve increases the BRT on the TAV leaflets. This may act as a permissive factor in valve thrombosis.

Subarachnoid hemorrhage in a patient with Abiotrophia defectiva endocarditis.

Endocarditis caused by Abiotrophia accounts for 5% of all cases of infective endocarditis (Roberts et al, Rev Infect Dis. 1979;1:955-66) and 5% to 6% of all cases of streptococcal endocarditis (Bouvet, Eur Heart J. 1995;16(suppl B):24-7; Brouqui et al, Clin Microbiol Rev. 2001;14:177-207). This endocarditis is associated with a high rate of embolization and treatment failure (Bouvet, Eur Heart J. 1995;16(suppl B):24-7). Neurological complications occur in 20% to 40% of all cases of infective endocarditis (Ossorio et al, Hosp Physician. 2003;39:21-4). Subarachnoid hemorrhage is a rare but devastating neurological complication. The authors presented a case of massive fatal subarachnoid hemorrhage in a patient with Abiotrophia defectiva endocarditis. To our knowledge, there are only 2 reported cases of mycotic aneurysms in Abiotrophia endocarditis, 1 of which was associated with subarachnoid hemorrhage (Leonard et al, N Engl J Med. 2001;344:233-4; Yang et al, Am J Med Sci. 2010;339:190-1).

Blood Stasis on Transcatheter Valve Leaflets and Implications for Valve-in-Valve Leaflet Thrombosis

BACKGROUND Leaflet thrombosis after valve-in-valve (ViV) procedure has been increasingly recognized. This study aimed to investigate the flow dynamics aspect of leaflet thrombosis by quantifying the blood stasis on the noncoronary and coronary leaflets of a surgical aortic valve (SAV) and a transcatheter aortic valve (TAV) in a ViV setting. METHODS Two computational models, representing a SAV and a TAV in ViV setting, were developed in a patient-specific geometry. Three-dimensional flow fields were obtained through a fluid-solid interaction modeling approach to study the difference in blood residence time (BRT) on the coronary and noncoronary leaflets. RESULTS Longer BRT was observed on the TAV leaflets compared with the SAV, specifically near the leaflet fixed boundary. Particularly, at the end of diastole, the areas of high BRT (≥1.2 seconds) on the surface of the TAV model leaflets were four times larger than those of the SAV model. The distribution of BRT on the three leaflets exhibited a similar pattern in the model for the TAV in ViV setting. That was in contrast to the SAV model where large areas of high BRT were observed on the noncoronary leaflet. CONCLUSIONS Geometric confinement of the TAV by the leaflets and the frame of the degenerated bioprosthesis that circumferentially surround the TAV stent increases the BRT on the leaflets, which may act as a permissive factor in the TAV leaflet thrombosis after ViV procedure. A similar distribution pattern of BRT observed on the TAV leaflets may explain the similar rate of occurrence of thrombosis on the three leaflets.

Carotid Artery Stenosis in the Setting of Transcatheter Aortic Valve Replacement: Clinical and Technical Considerations of Carotid Stenting.

OBJECTIVE No consensus exists regarding the safety and efficacy of treatment of carotid stenosis before transcatheter aortic valve replacement (TAVR). Our objective was to review our series of patients treated for carotid stenosis with stenting in the setting of severe aortic valve disease and TAVR to evaluate its safety and efficacy. METHODS We reviewed patients who underwent carotid stenting in the setting of preoperative work-up or after TAVR from August 2012 through January 2015. Perioperative patient outcomes were collected to assess the safety and efficacy of carotid stenting. RESULTS Five patients (4 men, 1 woman; median age, 83 years; range, 72-88 years) underwent successful carotid stenting before (median, 30 days before; range, 2 days-3 months) TAVR. The median extent of carotid stenosis was 80% (range, 75%-90%), but the diagnoses were incidental and all patients were asymptomatic. One patient suffered acute systolic heart failure during stenting requiring emergent balloon aortic valvuloplasty and vasopressor therapy. Median intensive care unit stay was 1 day (range, 1-16 days) for all patients, and 1 day for patients treated electively. The median hospital stay was 1 day (range, 1-16 days) for all patients, and 1 day for patients treated electively. All patients were discharged home. None suffered immediate or delayed neurological complications. CONCLUSIONS We successfully performed carotid stenting in 5 patients before TAVR for severe aortic pathology. These patients require intensive care and careful monitoring. Larger prospective studies are needed to determine whether carotid stenting in the setting of TAVR can provide long-term neurological benefits.

Transradial access mitigates bleeding benefit offered by bivalirudin over heparin in patients undergoing percutaneous coronary intervention: Insights from meta-analysis of randomized and observational studies

OBJECTIVE Recent randomized control trials (RCTs) showed conflicting efficacy and safety between bivalirudin and heparin during percutaneous coronary intervention (PCI). We aimed to perform an updated meta-analysis, including real-world and trial data to examine the factors affecting their risk-benefit ratio. METHODS We searched Medline, the Cochrane library, and meeting abstracts for studies comparing bivalirudin versus heparin during PCI. Random-effect meta-analyses for MACE (major adverse cardiovascular events), stent thrombosis (ST) and major bleeding were performed. p-Value <0.05 was considered statistically significant. RESULTS Meta-analysis of 20 RCTs and 31 observation studies (n=165,835) showed that bivalirudin and heparin were similar in the risk of MACE in RCTs (OR 1.05, 95% CI 0.97-1.13) and observational studies (OR 0.94, 95% 0.81-1.10). Major bleeding was lower with bivalirudin in both RCTs (OR 0.60, 95% CI 0.51-0.70) and observational studies (OR 0.56, 95% CI 0.47-0.68). However, in the metaregression analysis, every 10% increase of transradial access decreased the bleeding benefit of bivalirudin by 4.9% (p=0.046, adjusted for GPI and heparin loading dose). ST with bivalirudin was higher with ST-segment elevation myocardial infarction (STEMI) in RCTs (OR 1.51, 95% CI 1.15-1.99) but not in observational studies (p=0.65). CONCLUSIONS In this large meta-analysis, bivalirudin is associated with a lower risk of bleeding compared to heparin in both RCTs and observational studies, however, transradial PCI mitigated most of this bleeding benefit. Heparin should be the preferred agent in transradial PCI given its lower cost and comparable outcomes.

Effect of reduced cardiac output on blood stasis on transcatheter aortic valve leaflets: implications for valve thrombosis

AIMS There is an increasing awareness of leaflet thrombosis following transcatheter aortic valve implantation (TAVI) and valve-in-valve (ViV) procedures. Nevertheless, the predisposing factors affecting transcatheter aortic valve (TAV) thrombosis have remained unclear. This study aimed to quantify the effects of reduced cardiac output (CO) on blood stasis on the TAV leaflets as a permissive factor for valve thrombosis. METHODS AND RESULTS An idealised computational model representing a TAV was developed in a patient-specific geometry. Three-dimensional flow fields were obtained via a fluid-solid interaction modelling approach at different COs: 5.0, 3.5, 2.0 L/min. Blood residence time (BRT) was subsequently calculated on the leaflets. An association between reduced CO and increased blood stasis on the TAV leaflets was observed. At the end of diastole, larger areas of high BRT (>1.2 s) were observed at the leaflets fixed edge at low COs. Such areas were calculated to be 2, 8, and 11% of the total surface area of leaflets at CO=5.0, 3.5, and 2.0 L/min, respectively, indicating a ~sixfold increase of BRT on the leaflets from the highest to the lowest CO. CONCLUSIONS This study indicates an association between reduced CO and increased blood stasis on the TAV leaflets which can be regarded as a precursor of valve thrombosis.