Diversity and determinants of the sigmoid septum and its impact on morphology of the outflow tract as revealed using cardiac computed tomography

Optimal left ventricular diameter measurement in subjects with sigmoid septum: comparison with three-dimensional left ventricular volume

BACKGROUND

The purpose of this study was to determine the most appropriate measurement of left ventricular (LV) end-diastolic diameter for subjects with the sigmoid septum (SS) by measuring the LV end-diastolic diameter at the base and mid-ventricle and by examining the relationship between these measurements and the three-dimensional (3D) echocardiographic LV end-diastolic volume.

METHODS

In 91 patients who underwent echocardiography for screening cardiovascular abnormalities, the aorto-septal angle (ASA) was measured as an index of the sigmoid septum. LV end-diastolic diameter was measured at the base and mid-ventricular level (DDbase and DDmid, respectively), and their average value was calculated (DDavg). By using 3D echocardiography, LV end-diastolic volume (EDV3D) was measured.

RESULTS

Among 91 patients, 48 patients had narrow ASA (< 120 degrees) and were divided into the sigmoid septum (SS) group, and the remaining 43 patients were divided into the non-SS group. In the SS group, all DDbase, DDmid, and DDavg were significantly correlated with EDV3D (r = 0.59, 0.80, and 0.76, respectively), and the correlation coefficient between DDbase and EDV3D was significantly lower than that between DDmid and EDV3D (p < 0.01). On the other hand, in the non-SS group, all DDbase, DDmid, and DDavg were significantly correlated with EDV3D (r = 0.77, 0.85, and 0.84, respectively), and the correlation coefficient between DDbase and EDV3D was statistically comparable to that between DDmid and EDV3D (p = 0.12). ASA was significantly correlated with the difference of DDmid minus DDbase (r =  - 0.71, p < 0.001).

CONCLUSIONS

In patients with SS, DDmid and DDavg were well reflected the 3D echocardiographic LV end-diastolic volume.

Impact of an angulated aorto-septal relationship on cardio-cerebrovascular outcomes in patients undergoing hemodialysis

Aortic and valvular calcification are well-known risk factors for cardio-cerebrovascular events in patients undergoing hemodialysis. We investigated the clinical impact of an angulated aorto-septal angle as a result of aortic elongation due to aortic calcification on cardio-cerebrovascular outcomes in patients undergoing hemodialysis. We investigated 306 patients (mean age 65.4 years, 68% male) who underwent pre-scheduled routine echocardiography between April and September 2018. The angle between the anterior wall of the aorta and the ventricular septal surface (ASA) was quantified. We determined aortic and mitral valve calcification scores based on calcified cardiac changes; the aortic and mitral valve scores ranged between 0-9 and 0-6, respectively. The primary endpoint was a composite including cardio-cerebrovascular events and cardio-cerebrovascular death. The mean duration of dialysis among the patients in this analysis was 9.6 years. The primary endpoint was observed in 54 patients during the observational period (median 1095 days). Multivariable Cox proportional hazards analyses identified left ventricular ejection fraction (per 10% increase: hazard ratio [HR] 0.67; 95% confidential interval [CI] 0.53-0.84, P = 0.001), left ventricular mass index (per 10 g/m2 increase: HR 1.14; 95% CI 1.05-1.24, P = 0.001), ASA (per 10 degree increase: HR 0.69; 95% CI 0.54-0.88; P = 0.003), and aortic valve calcification score (HR 1.15; 95% CI 1.04-1.26, P = 0.005) as independent determinants of the primary endpoint. Kaplan-Meier analysis showed a higher incidence of the primary endpoint in patients with ASA <119.4 degrees than those with ASA ≥119.4 degrees (Log-rank P < 0.001). An angulated aorto-septal angle is an independent risk factor for cardio-cerebrovascular events and cardio-cerebrovascular death in patients undergoing hemodialysis.

Ratio of left ventricular outflow tract area to aortic annulus area and complete atrioventricular block after transcatheter aortic valve replacement for aortic stenosis

BACKGROUND

Mechanical compression of cardiac conduction system by transcatheter heart valves leads to complete atrioventricular block (CAVB) after transcatheter aortic valve replacement (TAVR). Bulging of ventricular septum in the left ventricular outflow tract (LVOT) may be associated with greater compression of conduction system, leading to irreversible CAVB.

OBJECTIVE

This study aimed to investigate the association of ventricular septal bulging with TAVR-related CAVB and permanent pacemaker implantation (PPI).

METHODS

Among 294 consecutive patients with severe aortic stenosis who underwent TAVR between July 2017 and February 2023, 271 were included in the analysis. As a quantitative evaluation of bulging of the ventricular septum, the ratio of LVOT area to aortic annulus area (L/A ratio) was measured at the systolic phase of computed tomography images.

RESULTS

TAVR-related CAVB occurred in 64 patients (23.6%). Twenty-eight patients (10.3%) required PPI. The optimal thresholds of L/A ratio for predicting TAVR-related CAVB and PPI were 1.0181 and 0.985, respectively. Patients with less than the cut-off values had higher rate of TAVR-related CAVB and PPI than those above (28.3% vs 13.1%, p = 0.0063; 14.7% vs 4.4%, p = 0.0077, respectively). A multivariate analysis showed that L/A ratio < 1.0181 was an independent predictor of TAVR-related CAVB (odds ratio [OR] 2.65, p = 0.011), in addition to prior right bundle branch block (OR 3.76, p = 0.0005), use of a self-expanding valve (OR 1.99, p = 0.030), and short membranous septum length (OR 0.96, p = 0.037). Only L/A ratio < 0.985 was independently associated with PPI (OR 3.70, p = 0.011).

CONCLUSION

Low L/A ratio is a predictor of TAVR-related CAVB and PPI.

Real-world clinical outcomes of percutaneous transluminal septal myocardial ablation for patients with drug-refractory hypertrophic obstructive cardiomyopathy: results from a retrospective multicenter registry of non-high-volume centers

Percutaneous transluminal septal myocardial ablation (PTSMA) is a well-established interventional therapy for drug-refractory hypertrophic obstructive cardiomyopathy (HOCM) as an alternative to surgical myectomy. Although guidelines recommend that PTSMA should be performed in institutions with extensive experience, it is not centralized to such high-volume centers in real-world clinical practice. Thus, this study aimed to assess the feasibility of PTSMA in non-high-volume centers. We retrospectively examined patients with HOCM who underwent PTSMA between August 2012 and May 2020 at four institutions that experienced fewer than 20 cases of PTSMA procedures. The primary clinical endpoint was a composite of safety (all-cause death, electrical defibrillation for ventricular tachycardia or fibrillation, cardiac tamponade, permanent pacemaker implantation, and repeated interventions) and efficacy endpoints (repeated interventions [PTSMA or surgical myectomy]). Fifty-eight consecutive patients were enrolled. During the 30-day follow-up, no major clinical adverse events were noted except three patients (5.2%) requiring permanent pacemaker implantation for complete atrioventricular block. The percentage of patients with New York Heart Association functional class 1 or 2 significantly increased from 8.6 to 100% (p < 0.001). In the Cox proportional hazard model, left ventricular outflow tract pressure gradient at rest ≥ 30 mmHg (hazard ratio [HR] 6.56; 95% confidence interval [CI] 1.44-29.90; p = 0.015) and mitral regurgitation grade ≥ 3 (HR 10.75; 95% CI 1.81-63.79; p = 0.009) at the 30-day follow-up were associated with a composite of major clinical adverse events. The current study demonstrated that 58 patients who underwent PTSMA in non-high-volume centers had favorable 30-day clinical outcomes, with a primary composite endpoint rate of 5.2%. A prospective study with a larger sample size and longer follow-up is warranted to verify the safety and efficacy of PTSMA in non-high-volume centers.