Mamoo Nakamura

Impact of coronary artery remodeling on clinical presentation of coronary artery disease: an intravascular ultrasound study.

OBJECTIVES We examined the association between the features of the culprit lesion in coronary artery disease (CAD) and clinical presentation as shown by intravascular ultrasound (IVUS). BACKGROUND The association between coronary remodeling pattern and clinical presentation of CAD is unclear. METHODS We analyzed 125 selected patients who underwent preintervention IVUS. Acute myocardial infarction (AMI) and unstable angina pectoris (UAP) were categorized as an acute coronary syndrome (ACS), and stable angina pectoris (SAP) and old myocardial infarction (OMI) as stable CAD. Coronary remodeling patterns and plaque morphology of the culprit lesion obtained by IVUS were analyzed in terms of their association with clinical presentation or angiographic morphology. RESULTS Angiographically complex lesions were associated with ACS and OMI. In patients with a complex lesion, positive remodeling was observed more frequently than in those with a simple lesion. In AMI and UAP, positive remodeling was observed more frequently than in SAP and OMI (82% vs. 78% vs. 33% vs. 40%, respectively, p < 0.0001). The remodeling ratio was greater in AMI and UAP than in SAP and OMI (1.26 +/- 0.15 vs. 1.11 +/- 0.10 vs. 0.94 +/- 0.11 vs. 0.96 +/- 0.13, respectively, p < 0.0001). Furthermore, within ACS, the remodeling ratio was greater in AMI than in UAP (1.26 +/- 0.15 vs. 1.11 +/- 0.10, respectively, p < 0.05), whereas the frequency of positive remodeling was not different. CONCLUSIONS Positive remodeling was more frequently observed in ACS than in stable CAD. Moreover, the degree of positive remodeling was greater in AMI than in UAP. These results may reflect the impact of remodeling types and its degree in the culprit lesion of CAD on clinical presentation.

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.

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.

Impact of peri-stent remodeling on restenosis : A volumetric intravascular ultrasound study

BackgroundVessel remodeling is an important mechanism of late lumen loss after nonstent coronary interventions. However, its impact on in-stent restenosis has not been systematically investigated. Methods and ResultsSerial volumetric intravascular ultrasound analyses (poststent and follow-up) were performed in 55 lesions treated with a balloon-expandable stent (ACS MultiLink) using standard stent deployment techniques. The vessel volume (VV), lumen volume (LV), and volume bordered by the stent (SV) were measured using Simpson’s method. The volume of plaque and neointima outside the stent (peri-stent volume, PSV) and volume of neointima within the stent (intrastent volume) were also measured. The change of each parameter during the follow-up period (follow-up minus poststent) was calculated and then divided by SV to normalize these values (designated as percent change [%&Dgr;]). As expected, %&Dgr;PSV directly correlated with %&Dgr;VV (P <0.0001, r =0.935), with no significant &Dgr;SV. A highly significant inverse correlation was seen between %&Dgr;PSV and the percent change of intrastent volume (P <0.0001, r =0.517). Consequently, %&Dgr;LV significantly correlated with peri-stent remodeling, as measured by %&Dgr;VV (P <0.0001, r =0.602). ConclusionPositive remodeling of the vessel exterior to a coronary stent occurs to a variable degree after stent implantation. There is a distinct trade-off between positive remodeling and in-stent hyperplasia: in segments in which the degree of peri-stent remodeling is less, intrastent neointimal proliferation is greater and accompanied by more significant late lumen loss.

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).

Impact of pulmonary hypertension on outcomes in patients with functional mitral regurgitation undergoing percutaneous edge-to-edge repair.

Preexisting pulmonary hypertension (PH) is associated with poor outcomes after surgical mitral valve repair for functional mitral regurgitation (FMR). However its clinical impact on MitraClip therapy remains unknown. The aim of this study was therefore to evaluate the impact of preexisting PH on MitraClip therapy for patients with FMR. Ninety-one consecutive patients who had FMR and who underwent the MitraClip procedure were studied. They were divided into 2 groups on the basis of pulmonary artery systolic pressure: the PH group (n = 48) and the non-PH group (n = 43). PH was defined as pulmonary artery systolic pressure >50 mm Hg using Doppler echocardiography. Procedural success (defined as magnetic resonance reduction to grade 2+ or less) and 30-day mortality were similar in the 2 groups. At 12 months, New York Heart Association functional class had improved to class I or II in most patients in the PH (from 2.9% to 94.3%) and non-PH (from 9.4% to 96.9%) groups. The mean pulmonary artery systolic pressure of the PH group significantly decreased from baseline but remained higher than that of the non-PH group (50.8 ± 15.3 vs 36.7 ± 11.6 mm Hg, p <0.001). After a mean of 25.0 ± 16.9 months of follow-up, Kaplan-Meier analysis demonstrated significantly higher all-cause mortality in the PH group. In Cox regression analysis, preexisting PH was the most powerful predictor of all-cause mortality (hazard ratio 3.731, 95% confidence interval 1.653 to 8.475, p = 0.002). In conclusion, MitraClip therapy reduced FMR and alleviated symptoms with an excellent early safety profile in the PH and non-PH groups. However, preexisting PH was associated with worse all-cause mortality.

Comparison of SAPIEN 3 and SAPIEN XT transcatheter heart valve stent-frame expansion: evaluation using multi-slice computed tomography

Aims Stent-frame morphology of the newer-generation, balloon-expandable transcatheter heart valve (THV), the SAPIEN 3 (S3), after transcatheter aortic valve implantation (TAVI) is unknown. We evaluated the THV stent-frame morphology post TAVI of the S3 using multi-slice computed tomography (MSCT) compared with the prior-generation THV, SAPIEN XT (S-XT). Methods and results A total of 94 consecutive participants of RESOLVE registry (NCT02318342) had MSCT after balloon-expandable TAVI (S3 = 39 and S-XT = 55). The morphology of the THV stent-frame was evaluated for expansion area and eccentricity at the THV-inflow, native annulus, mid-THV and THV-outflow levels. Mean %-expansion area for the S3 and the S-XT was 100.9 ± 5.7 and 96.1 ± 5.5%, respectively (P < 0.001). In the S3 group, the THV-inflow level had the largest value of %-expansion area, which decreased from THV-inflow to mid-THV level (105.2 ± 6.4 to 96.5 ± 5.9%, P < 0.001). However, in the S-XT group, %-expansion area increased from THV-inflow level to mid-THV level (93.2 ± 6.2 to 95.1 ± 6.1%, P = 0.0058). On nominal delivery balloon volume, the S3 in 88.5% of cases had overexpansion at the THV-inflow level. The observed degree of THV oversizing of the S3 was significantly lower than the S-XT (6.3 ± 8.6 vs. 11.8 ± 8.5%, P = 0.0027). Nonetheless, the incidence of post-procedural paravalvular aortic regurgitation (PVR) ≥ mild following the S3 TAVI was also significantly lower than the S-XT TAVI (17.9 vs. 43.6%, P = 0.014). Conclusion The newer-generation, balloon-expandable device, the S3, has a flared inflow morphology, whereas the prior-generation device, the S-XT, has relatively constrained inflow morphology post TAVI. This may contribute to a lesser degree of PVR with the S3.

Clinical impact of coronary protection during transcatheter aortic valve implantation: first reported series of patients.

AIMS Coronary protection with guidewires and an undeployed coronary balloon or stent positioned in the coronary artery is a pre-emptive technique to manage coronary obstruction during transcatheter aortic valve implantation (TAVI). We investigated the feasibility and safety of left main (LM) protection during TAVI. METHODS AND RESULTS Twenty-five out of 623 patients who underwent TAVI at our institute were deemed to be at increased risk of LM compromise mainly due to a low LM ostium height, significant LM disease or a previous bioprosthetic valve. A pre-emptive LM protection technique was therefore used in these cases. Five patients (20%) had pre-TAVI significant non-revascularised LM stenosis, and four patients (16%) had a prior LM ostial stent without pre-TAVI in-stent restenosis. Twelve patients had extremely low LM height (mean height 6.7±2.4 mm; range 1.1-8.9 mm). Seven patients (25%) had valve-in-valve (VIV) procedures. LM compromise occurred in five out of 25 cases; all were treated successfully with emergency LM stenting. Nine patients underwent successful planned LM procedures following TAVI. CONCLUSIONS The LM protection technique should be considered in patients deemed to be at increased risk of LM compromise. This was found to be helpful in the prompt diagnosis and treatment of LM compromise following TAVI.

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).