Short membranous septum length in bicuspid aortic valve stenosis increases the risk of conduction disturbances.

BACKGROUND: Distinct anatomical features predispose bicuspid AS patients to conduction disturbances after TAVR. This study sought to evaluate whether the incidence of permanent pacemaker implantation (PPMI) and left bundle branch block (LBBB) in patients with bicuspid aortic stenosis (AS) following transcatheter aortic valve replacement (TAVR) is related to an anatomical association between bicuspid AS and short membranous septal (MS) length. METHODS: Sixty-seven consecutive patients with bicuspid AS from a Bicuspid AS TAVR multicenter registry and 67 propensity-matched patients with tricuspid AS underwent computed tomography before TAVR. RESULTS: MS length was significantly shorter in bicuspid AS compared with tricuspid AS (6.2 ± 2.5 mm vs. 8.4 ± 2.7 mm, respectively; p < 0.001). In patients with bicuspid AS, MS length and aortic valve calcification were the most powerful pre-procedural independent predictors of PPMI or LBBB (odds ratio [OR]: 1.38, 95% confidence interval [CI]: 1.15 to 1.55, p = 0.003 and OR: 1.92, 95% CI: 1.1 to 3.34, p = 0.022, respectively). When taking into account pre- and post-procedural parameters, aortic valve calcification and the difference between MS length and implantation depth were the most powerful independent predictors of PPMI or LBBB in patients with bicuspid AS (OR: 1.82, 95%: 1.1 to 3.1, p = 0.027; OR: 1.25, 95% CI: 1.10 to 1.38, p = 0.003). CONCLUSION: MS length, which was significantly shorter in bicuspid AS compared with tricuspid AS, aortic valve calcification, and device implantation deeper than MS length predict PPMI or LBBB in bicuspid AS after TAVR.

Feasibility and Robustness of 3T Magnetic Resonance Angiography Using Modified Dixon Fat Suppression in Patients With Known or Suspected Peripheral Artery Disease.

Objective: Contrast-enhanced magnetic resonance angiography (CE-MRA) is a well-established non-invasive imaging technique for the assessment of peripheral artery disease (PAD). A subtractionless method using modified Dixon (mDixon) fat suppression showed superior image quality at 1.5T over the common subtraction method, using a three-positions stepping table approach with a single dose of contrast agent. The aim of this study was to investigate the feasibility of subtractionless first-pass peripheral MRA at 3T in patients with known or suspected PAD and to compare the performance in terms of vessel-to-background contrast (VBC), signal-to-noise ratio (SNR), and subjective image quality to conventional subtraction MRA. Methods: Ten patients [mean age 69 years ± 12 standard deviation (SD)] with known or suspected PAD were examined on a clinical 3T scanner (Ingenia, Philips Healthcare, Best, Netherlands) at three table positions using subtractionless and subtraction first-pass peripheral MRA. Two readers rated image quality on a four- point scale. Interobserver agreement was expressed in quadratic weighted κ values. VBC was assessed with a semi-automated process and SNR was compared in a healthy volunteer. Results: Subjective image quality was significantly better with the subtractionless method overall (mean image quality for mDixon imaging: 2.88 ± 0.32 SD vs. for subtraction imaging: 2.57 ± 0.48 SD; P < 0.001) and per table position (abdominal position: 2.88 ± 0.32 vs. 2.57 ± 0.48 SD; P < 0.001); upper leg position: (2.97 ± 0.15 SD vs. 2.68 ± 0.37 SD; P < 0.001; lower leg position: 2.60 ± 0.50 SD vs. 2.13 ± 0.60 SD; P < 0.001). Vessel-to-background contrast increased by 22% with the subtractionless method overall (mean VBC for mDixon imaging: 23.16 ± 8.4 SD vs. for subtraction imaging: 19.00 ± 8.1 SD; factor 1.22, P < 0.001). SNR was 82% higher with the subtractionless method (overall SNR gain 1.82; P < 0.001). Conclusion: This study demonstrated the feasibility and robustness of subtractionless first-pass peripheral MRA at 3T in patients with known or suspected PAD using a three- positions stepping table approach with a single dose of contrast agent. It showed increased image quality compared to the conventional subtraction method and superior performance in terms of SNR and vessel-to-background contrast.

Effect of Intramural Course of Coronary Arteries Assessed by Computed Tomography Angiography in Patients With Hypertrophic Cardiomyopathy.

This study evaluated the prevalence, anatomical pattern, and prognostic implications of an intramural course of the coronary arteries in patients with hypertrophic cardiomyopathy (HC). The study population consisted of 92 patients with HC and 100 patients without HC. The presence of an intramural course of the coronary arteries was evaluated by coronary computed tomography angiography (CTA), and its length and depth were measured. During follow-up, the occurrence of unstable angina requiring hospitalization, myocardial infarction, and all-cause mortality was evaluated. An intramural course of the coronary arteries was more common in patients with HC than patients without HC (62% vs 25%, p <0.001). In the patients with an intramural coronary artery course, those with HC had a longer course (29.1 ± 15.3 mm vs 23.0 ± 13.0 mm; p = 0.037) with deeper penetration into the left ventricular myocardium (2.8 ± 1.2 mm vs 2.1 ± 0.8 mm; p = 0.007) and more involvement of multiple coronary arteries (38% vs 4%; p <0.001). During follow-up (mean 5.5 ± 3.5 years), cardiac events occurred in 17 of 57 patients (29.8%) with an intramural course and 11 of 35 (31.4%) without an intramural course (p = 0.87). On Kaplan-Meier survival analysis, there was no difference in cumulative event rate between HC patients with or without an intramural course (p = 0.89, log rank test). In conclusion, patients with HC have a high rate of an intramural course of the coronary arteries on CTA. The number of involved arteries and the length and depth of the intramural course differ between patients with and without HC, but apparently have no association with worse clinical outcomes.

Prevalence and morphology of myocardial crypts in normal and hypertrophied myocardium by computed tomography.

Myocardial crypts can be recognized in patients with hypertrophic cardiomyopathy (HCM) using magnetic resonance imaging, but similar studies using computed tomography (CT) are sparse. The aim of the present study was to evaluate the prevalence and morphology of myocardial crypts in patients with HCM, arterial hypertension, and aortic valve stenosis using contrast-enhanced CT. We also investigated the added value of a finding of myocardial crypts on CT scan to the diagnosis of HCM. The study cohort included 73 patients with HCM, 100 patients with arterial hypertension, 120 patients with aortic valve stenosis, and 100 subjects without cardiovascular disease (normal control group). All underwent evaluation for the presence and dimensions of myocardial crypts using 256-slice CT. Crypts were identified in 18 patients (24.7%) with HCM, 7 patients (7%) with hypertension, 8 patients (6.7%) with aortic valve stenosis, and 4 (4%) normal subjects (P < 0.001). Values of crypt length, width, area, and penetration into myocardium were highest in the HCM group. Crypt area differentiated patients with HCM from patients with arterial hypertension and aortic valve stenosis, and from normal control subjects. Crypt area was an accurate predictor of HCM, with an area under the receiver-operator characteristic curve of 0.88 (95% CI 0.80-0.96). Myocardial crypts identified by CT are more prevalent and larger in area in HCM than in arterial hypertension and aortic valve stenosis. Crypt area could potentially help to improve the diagnosis of HCM by CT beyond the assessment of left ventricular thickness or mass.

Iliofemoral artery lumen volume assessment with three dimensional multi-detector computed tomography and vascular complication risk in transfemoral transcatheter aortic valve replacement.

BACKGROUND: Transfemoral Transcatheter Aortic Valve Replacement (TAVR) carries a risk of Vascular Complications (VCs) at the access site. The currently used measures for assessing the risk for VCs are not accurate enough, and sometimes fail to predict them. We therefore aimed to examine whether Iliofemoral artery lumen volume (IFV) assessment with 3-dimensional computed tomography (CT) predicts VCs after transfemoral TAVR. METHODS: We identified 45/560 trans-femoral TAVR patients with VC, then performed nearest neighbor 1:1 matching for patients with no VC, matching for age, sex, TAVR year, valve size and type, closure-device, sheath size and peripheral vascular disease. IFV, minimal diameter, tortuosity, and calcification were measured, and their diagnostic performance assessed. RESULTS: The final analysis included 45 patients with and 45 patients without VCs. The two groups were well balanced. For all patients, median IFV was 8.65 ml (IQR 6.5-11.95). IFV was lower in patients with VC compared to patients without VC: 7.10 ml (IQR 5.4-9.0) vs. 10.10 ml (IQR 8.3-13.3), p < 0.001. VC risk had marginal association with iliofemoral artery minimal diameter (p = 0.06) and no association with tortuosity or calcification. Compared with other measurements, IFV had the most favorable receiver operating curve for the prediction of VC, with an area under the curve (AUC) of 0.78. CONCLUSION: IFV measurement using 3-dimensional CT is significantly associated with VCs in transfemoral TAVR patients and might be superior to currently accepted parameters. IFV should be further studied among extended cohorts of TAVR treated patients as a novel tool for VC risk assessment prior to transfemoral TAVR.

The impact of body mass index on clinical outcomes after acute myocardial infarction.

BACKGROUND: Several studies indicated that an elevated body mass index (BMI) is associated with a lower rate of mortality in patients with acute myocardial infarction (AMI). However, the existence of the obesity paradox in AMI patients remains controversial. METHODS: We examined the association of BMI and clinical outcomes in 2157 patient with AMI (mean follow-up of 26 months). BMI was categorized into 9 groups (<18.5, 18.5 to 20.9, 21.0 to 23.4, 23.5 to 24.9, 25.0 to 26.4, 26.5 to 27.9, 28.0 to 29.9, 30.0 to 34.9, and ≥35.0 kg/m2). Cox regression was used to calculate hazard ratios (HR) for the various BMI categories, adjusting for the clinical variables, left ventricular ejection fraction, and hemoglobin level. RESULTS: BMI had a U-shaped association with mortality. Relative to the lowest mortality group (BMI of 26.5 to 27.9 kg/m2), the adjusted HRs for mortality were increased only in the lower (HR 2.3; 95% CI 1.3-4.2) and upper (HR 1.8; 95% 1.2-2.9) BMI categories. There was a significant interaction between BMI and anemia (P=0.0003) such that the U-shaped relationship between BMI and mortality was present mainly in patients with anemia. Patients in the lower and upper BMI categories and concomitant anemia had a striking increase in mortality (adjusted HR 5.1, 95% CI 1.9-11.7 and 3.2, 95% CI 1.5-7.0, respectively). CONCLUSION: Both obesity and underweight are associated with increased mortality in patients with AMI. The risk of mortality is particularly high among underweight and obese patients with anemia.

Hyponatremia and long-term mortality in survivors of acute ST-elevation myocardial infarction.

BACKGROUND: Hyponatremia, a marker of neurohormonal activation, is a common electrolyte disorder among patients with acute ST-elevation myocardial infarction. The long-term prognostic value of hyponatremia during the acute phase of infarction is not known. METHODS: We studied 978 patients with acute ST-elevation myocardial infarction and without a history of heart failure who survived the index event. During the hospital stay, sodium levels were obtained on admission and at 24, 48, and 72 hours. The median duration of follow-up after hospital discharge was 31 months (range, 9-61 months). RESULTS: Hyponatremia, defined as a mean serum sodium level less than 136 mEq/L, was present during admission in 108 patients (11.0%). In a multivariable Cox proportional hazards model adjusting for other potential clinical predictors of mortality and for left ventricular ejection fraction, hyponatremia during admission remained an independent predictor of postdischarge death (hazard ratio [HR], 2.0; 95% confidence interval [CI], 1.3-3.2; P = .002). Hyponatremia during admission was also independently associated with postdischarge readmission for heart failure (HR, 1.6; 95% CI, 1.1-2.6; P = .04). When serum sodium level was used as a continuous variable, the adjusted HR for death or heart failure was 1.12 for every 1-mEq/L decrease (95% CI, 1.07-1.18; P<.001). CONCLUSION: Hyponatremia in the early phase of ST-elevation myocardial infarction is a predictor of long-term mortality and admission for heart failure after hospital discharge, independent of other clinical predictors of adverse outcome and left ventricular ejection fraction.

Anti-fibrotic activity of NK cells in experimental liver injury through killing of activated HSC.

BACKGROUND/AIMS: We have investigated the role of natural killer (NK) cells in hepatic fibrogenesis. Mouse NK cells express both inhibitory/activating-killing-immunoglobulin-related-receptors (iKIR/aKIR) specific for Class-I-molecules. METHODS: Hepatic fibrosis induced by carbon-tetrachloride (CCl4) was compared between wild-type (WT) male-BALBc; combined-immunodeficiency (SCID, lacking B/T-cells); and SCID-BEIGE-mice (lacking B/T/NK cells), and naive mice. RESULTS: Hepatic fibrosis significantly increased in all CCl4-treated groups. SCID-BEIGE mice had more fibrosis than SCID-mice (P<0.0001) as assessed by morphometry of sirius-red stained tissue sections. Following fibrosis, hepatic NK cells significantly decreased, the aKIR:iKIR-ratio significantly increased while Class-I expression on HSC decreased (P<0.001). Both freshly isolated and in situ HSC displayed a significant increase in cellular apoptosis following fibrosis induction. Confocal microscopy demonstrated the direct adhesion of NK cells to HSC in mouse liver sections and in vitro human NK/HSC co-culture. In human HSC there was decreased Class-I expression and increased apoptosis as well, which was further increased following blocking of either HSC-related Class-I or NK-related killer inhibitory receptors. Apoptosis was inhibited by pre-incubation of NK cells with the granzyme inhibitor 3,4-dichloroisocoumarin. CONCLUSIONS: During liver injury, NK cells have an anti-fibrotic activity at least in part through stimulation of HSC killing.