Niraj Doctor

Cross-Sectional Computed Tomographic Assessment Improves Accuracy of Aortic Annular Sizing for Transcatheter Aortic Valve Replacement and Reduces the Incidence of Paravalvular Aortic Regurgitation

OBJECTIVES In an effort to define the gold standard for annular sizing for transcatheter aortic valve replacement (TAVR), we sought to critically analyze and compare the predictive value of multiple measures of the aortic annulus for post-TAVR paravalvular (PV) regurgitation and then assess the impact of a novel cross-sectional computed tomographic (CT) approach to annular sizing. BACKGROUND Recent studies have shown clear discrepancies between conventional 2-dimensional (2D) echocardiographic and CT measurements. In terms of aortic annular measurement for TAVR, such findings have lacked the outcome analysis required to inform clinical practice. METHODS The discriminatory value of multiple CT annular measures for post-TAVR PV aortic regurgitation was compared with 2D echocardiographic measures. TAVR outcomes with device selection according to aortic annular sizing using a traditional 2D transesophageal echocardiography-guided or a novel CT-guided approach were also studied. RESULTS In receiver-operating characteristic models, cross-sectional CT parameters had the highest discriminatory value for post-TAVR PV regurgitation: This was with the area under the curve for [maximal cross-sectional diameter minus prosthesis size] of 0.82 (95% confidence interval: 0.69 to 0.94; p < 0.001) and that for [circumference-derived cross-sectional diameter minus prosthesis size] of 0.81 (95% confidence interval: 0.7 to 0.94; p < 0.001). In contrast, traditional echocardiographic measures were nondiscriminatory in relation to post-TAVR PV aortic regurgitation. The prospective application of a CT-guided annular sizing approach resulted in less PV aortic regurgitation of grade worse than mild after TAVR (7.5% vs. 21.9%; p = 0.045). CONCLUSIONS Our data lend strong support to 3-dimensional cross-sectional measures, using CT as the new gold standard for aortic annular evaluation for TAVR with the Edwards SAPIEN device.

Aortic annular sizing for transcatheter aortic valve replacement using cross-sectional 3-dimensional transesophageal echocardiography.

OBJECTIVES This study compared cross-sectional three-dimensional (3D) transesophageal echocardiography (TEE) to two-dimensional (2D) TEE as methods for predicting aortic regurgitation after transcatheter aortic valve replacement (TAVR). BACKGROUND Data have shown that TAVR sizing using cross-sectional contrast computed tomography (CT) parameters is superior to 2D-TEE for the prediction of paravalvular aortic regurgitation (AR). Three-dimensional TEE can offer cross-sectional assessment of the aortic annulus but its role for TAVR sizing has been poorly elucidated. METHODS All patients had severe symptomatic aortic stenosis and were treated with balloon-expandable TAVR in a single center. Patients studied had both 2D-TEE and 3D imaging (contrast CT and/or 3D-TEE) of the aortic annulus at baseline. Receiver-operating characteristic curves were generated for each measurement parameter using post-TAVR paravalvular AR moderate or greater as the state variable. RESULTS For the 256 patients studied, paravalvular AR moderate or greater occurred in 26 of 256 (10.2%) of patients. Prospectively recorded 2D-TEE measurements had a low discriminatory value (area under the curve = 0.52, 95% confidence interval: 0.40 to 0.63, p = 0.75). Average cross-sectional diameter by CT offered a high degree of discrimination (area under the curve = 0.82, 95% confidence interval: 0.73 to 0.90, p < 0.0001) and mean cross-sectional diameter by 3D-TEE was of intermediate value (area under the curve = 0.68, 95% confidence interval: 0.54 to 0.81, p = 0.036). CONCLUSIONS Cross-sectional 3D echocardiographic sizing of the aortic annulus dimension offers discrimination of post-TAVR paravalvular AR that is significantly superior to that of 2D-TEE. Cross-sectional data should be sought from 3D-TEE if good CT data are unavailable for TAVR sizing.

Predictive accuracy of SYNTAX score for predicting long-term outcomes of unprotected left main coronary artery revascularization.

The American College of Cardiology/American Heart Association recently updated recommendations for percutaneous coronary intervention (PCI) of unprotected left main coronary artery (ULMCA) disease from class III to II(b) according to the results of the SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery (SYNTAX) trial. The SYNTAX score is an angiographic tool using solely the coronary anatomy. We studied the effect of co-morbidities (Parsonnets score) on the ability of the SYNTAX score to predict long-term outcomes in patients with ULMCA disease treated by revascularization. A total of 328 patients underwent revascularization of ULMCA from April 2003 to February 2007. Of the 328 patients, 120 underwent PCI (median follow-up 973 days) and 208 underwent coronary artery bypass grafting (CABG) (median follow-up 1,298 days). The ability of the SYNTAX score to predict outcomes was assessed using the Cox proportional hazards model. The outcomes between the PCI and CABG groups were compared by propensity analysis. The median SYNTAX score was 26 in the PCI and 28 in the CABG group (p = 0.5). In the PCI group, greater quartiles were associated with worse survival (62.1% at SYNTAX score of ≥36 vs 82.4% at SYNTAX score of <36, p = 0.03) and all-cause mortality, myocardial infarction, cerebrovascular events, and target vessel revascularization-free (MACCE) survival (47.7%, SYNTAX score ≥20 vs 76.6%, SYNTAX score <20, p = 0.02). Using the Parsonnet score as a covariate, the SYNTAX score continued to be an independent predictor of MACCE and demonstrated a trend toward predicting mortality in the PCI group. In contrast, the SYNTAX score did not predict the outcomes for the CABG group. No difference was found in mortality between the PCI and CABG groups for ULMCA disease, regardless of coronary complexity; although greater SYNTAX scores were associated with increased MACCE rates with PCI compared to CABG. Both the coronary anatomy (SYNTAX score) and co-morbidities (Parsonnets score) predicted long-term outcomes for PCI of ULMCA disease. In contrast, the SYNTAX score did not predict the outcomes after CABG. In conclusion, the ideal scoring system to guide an appropriate revascularization decision for ULMCA disease should take into account both the coronary anatomy and the co-morbidities.

Meta-Analysis of Incidence, Clinical Characteristics and Implications of Stent Fracture

A meta-analysis of published studies was conducted to evaluate the incidence, predictors, and clinical outcomes of stent fractures. Eight studies with 108 stent fractures in 5,321 patients were analyzed using the Bayesian method. Study end points included in-stent restenosis (ISR) and target lesion revascularization (TLR). The mean incidence of stent fracture per patient was 4.0% (95% confidence interval 0.4% to 16.3%). All cases, except 1, were reported with sirolimus-eluting stents. The incidence of stent fracture was 30.4% in the left anterior descending coronary artery, 10.9% in the left circumflex coronary artery, 56.4% in the right coronary artery, < 0.01% in the left main coronary artery, and 1.7% in saphenous vein grafts. The probability of stent fracture was significantly higher in the right coronary artery than in the left anterior descending and left circumflex lesions (p < 0.01). Left main stents were less likely to fracture compared to those in all other vessels (p < 0.01). The probability of stent fracture was significantly increased in overlapping stents (7.5% vs 2.1%, p = 0.01) and long stents (46 vs 32.5 mm, p < 0.01). Lesions with stent fractures had higher rates of ISR (38% vs 8.2%, p < 0.01) and TLR (17% vs 5.6%, p < 0.01). Conversely, the probability of stent fractures was higher in patients with ISR (12.8% vs 2.1%, p < 0.01) and TLR (8.8% vs 2.7%, p < 0.01). In conclusion, although not always associated with clinical sequelae, the probability of ISR and TLR is increased with stent fracture. Conversely, the probability of stent fractures is increased in lesions with ISR or TLR, thus raising the need for surveillance and management guidelines for at-risk patients.

A revised methodology for aortic-valvar complex calcium quantification for transcatheter aortic valve implantation

AIMS We sought to optimize a method for quantification of the calcium in the aortic-valvar complex for the prediction of significant paravalvular leak (PVL) after transcatheter aortic valve implantation (TAVI). METHODS AND RESULTS All patients had severe symptomatic aortic stenosis and were treated with balloon-expandable TAVI (Sapien/Sapien-XT, Edwards Lifesciences LLC, Irvine, CA, USA). In order to correct for precise annular sizing, only patients with available contrast computed tomography (CT) data for measurements were included (n = 198). Paravalvular leak was quantified using peri-procedural transoesophageal echocardiography by Valve Academic Research Consortium-2 (VARC-2) criteria (grade ≥ moderate was considered significant). A detailed region-of-interest methodology separated quantification of calcium in each of the aortic leaflets to that in the left ventricular outflow tract (LVOT) and was used to predict PVL in receiver operator characteristic curve analyses. For non-contrast scans, the greatest discriminatory value for PVL was seen at the 450 Hounsfield Unit (HU) threshold for detection (volume ≥626 mm(3)), whereas for contrast scans it was at 850 HU (≥235 mm(3)). Left ventricular outflow tract calcium predicted PVL but only as a binary variable with no incremental value of quantification. In a multivariable binary logistic regression model, annulus area ≥ prosthesis area (OR 3.5, 95% CI 1.5-8.2, P = 0.005), contrast leaflet calcium volume (850-HU threshold) ≥235 mm(3) (OR 2.8, 95% CI 1.2-6.7, P = 0.023), and presence of LVOT calcium (OR 2.8, 95% CI 1.2-7.0, P = 0.022) were independent predictors for PVL ≥ moderate. CONCLUSION Both leaflet and LVOT calcium are significant predictors of PVL and exert an important synergistic influence on this complication, even in appropriately sized valves. With careful attention to thresholds for detection, clinically relevant leaflet calcium volumes can be identified with either non-contrast or contrast CT scans.

Complete percutaneous approach for arterial access in transfemoral transcatheter aortic valve replacement: A comparison with surgical cut‐down and closure

This study sought to investigate the immediate safety and feasibility of complete percutaneous access/closure of arteriotomy for device deployment compared to the surgical approach for transfemoral transcatheter aortic valve replacement (TAVR).

Heart-rate adjustment of transcatheter haemodynamics improves the prognostic evaluation of paravalvular regurgitation after transcatheter aortic valve implantation.

AIMS Paravalvular aortic regurgitation (PVAR) after balloon-expandable transcatheter aortic valve implantation (TAVI) remains difficult to quantify, and the utility of the AR index (ARi) to create a composite aortic insufficiency (CAI) score was an important advance. Heart rate (HR) influences the ARi but the clinical relevance of this phenomenon remains poorly appreciated. We sought to validate a new composite heart-rate-adjusted haemodynamic-echocardiographic aortic insufficiency (CHAI) score in the prognostic evaluation of PVAR after balloon-expandable TAVI. METHODS AND RESULTS The severity of PVAR was assessed immediately post TAVI by transoesophageal echocardiography (TOE) with simultaneous assessment of transcatheter haemodynamics. A total of 303 patients were studied. The CHAI score, incorporating the HR-adjusted diastolic-delta (HRA-DD, the difference between left ventricular and aortic diastolic pressures/HR*80), had a greater discriminatory value for one-year mortality than both PVAR by TOE (p=0.0018) and the previously proposed CAI score, based on the ARi without HR adjustment (p=0.0029). The CHAI score also better stratified percentage increases in left ventricular systolic chamber dimensions at one month and serum natriuretic peptide levels at one to three months. CONCLUSIONS Prognostication of PVAR in the intermediate range of echocardiographic severity remains unreliable and is greatly enhanced by the integration of heart-rate-adjusted transcatheter haemodynamics.

Major thrombocytopenia after balloon-expandable transcatheter aortic valve replacement: prognostic implications and comparison to surgical aortic valve replacement.

We sought to investigate the magnitude and clinical importance of thrombocytopenia post transcatheter aortic valve replacement (TAVR).

Comparison of long-term outcomes of drug-eluting stents and bare metal stents for saphenous vein graft stenosis.

Objective: Our aim was to compare the long‐term outcomes between drug‐eluting stents and bare‐metal stents for saphenous vein graft stenosis. Background: The ideal type of stent to treat saphenous vein graft stenosis has not been clearly established. Short‐term randomized controlled trial results comparing drug‐eluting stents with bare‐metal stents for saphenous vein graft stenosis are conflicting, intermediate‐term retrospective studies and meta‐analyses at two years suggest no difference in outcomes, and there are no long term follow‐up studies. The need for long term follow‐up data has become emerged with concern over late stent thrombosis. Methods: 246 saphenous vein graft patients undergoing stenting from August 2002–December 2008 were studied. Overall survival and event‐free survival were compared by Kaplan‐Meier method. Hazard ratios (HR) were calculated by Cox‐proportional hazards models. Results: We treated 133 patients with DES (median follow‐up four years) and 113 patients with BMS (median follow‐up four years) for SVG stenosis. Overall survival (77.0% ± 3.9% vs. 70.6% ± 4.6%, log‐rank P = 0.60) and MACE‐free survival (57.5% ± 4.6% vs. 56.8% ± 4.9, log‐rank P = 0.70) were not significantly different between the DES and BMS groups. Although BMS was associated with increased risk of target lesion revascularization (TLR) (freedom from TLR 85.2% ± 3.5% vs. 90.0% ± 3.0%, HR 2.07, 95% CI 0.97–4.42, log‐rank P = 0.05), there was no significant difference in the freedom from myocardial infarction (86.7% ± 3.3% vs. 88.7% ± 3.2%, log‐rank P = 0.39) or target vessel revascularization (77.1% ± 4.2% vs. 76.1% ± 4.2%, log‐rank P = 0.33) between the two groups. Conclusions: Although mortality is not statistically different between DES and BMS for SVG stenosis, BMS is associated with increased risk of revascularization, thus suggesting the superiority of DES over BMS in the long term.

Complications after transfemoral transcatheter aortic valve replacement with a balloon‐expandable prosthesis: The importance of preventative measures and contingency planning

Transcatheter aortic valve replacement (TAVR) with balloon‐expandable Edwards‐SAPIEN valve was superior to standard therapy in inoperable patients and noninferior to surgical aortic valve replacement in high surgical‐risk, but operable patients, with severe symptomatic aortic stenosis in the randomized controlled PARTNER trial. Since the first case of TAVR with a balloon‐expandable valve in 2002, several groups have reported their experience with balloon‐expandable valves with high‐procedural success. In the United States, the balloon‐expandable Edwards‐SAPIEN valve is the only transcatheter heart valve approved by the FDA for commercial use. Moreover, this is only in high‐risk inoperable patients. Despite increasing experience with the TAVR procedure, it can be associated with complications, which can be technically challenging, even for an experienced operator. Complications associated with TAVR include vascular complications, valve malpositioning, regurgitation, embolization, coronary compromise, conduction abnormalities, stroke/transient ischemic attack, acute kidney injury, cardiac tamponade, and hemodynamic collapse. A thorough understanding of the procedure is essential for pre‐emptive planning for procedural complications and early identification and management of complications are necessary for procedural success. We hereby review our experience of transfemoral TAVR with balloon‐expandable valves, offer practical tips to maximize the likelihood of procedural success, describe pre‐emptive strategies to prevent peri‐procedural complications and bailout measures to manage them, should they occur.