Elevated myocardial extracellular volume fraction is associated with the development of conduction pathway defects following transcatheter aortic valve replacement.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has become an established method of aortic stenosis treatment but suffers from the risk of heart block and pacemaker requirement. Risk stratification for patients who may develop heart block remains imperfect. Simultaneously, myocardial fibrosis as measured by cardiac magnetic resonance imaging (CMR) has been demonstrated as a prognostic indicator of ventricular recovery and mortality following TAVR. However, the association of CMR-based measures of myocardial fibrosis with post-TAVR conduction disturbances has not yet been explored. AIMS: We evaluated whether myocardial fibrosis, as measured by late gadolinium enhancement and extracellular volume (ECV) from CMR would be associated with new conduction abnormalities following TAVR. METHODS: One hundred seventy patients who underwent CMR within 2 months before TAVR were retrospectively reviewed. Septal late gadolinium enhancement (LGE) and ECV measurements were made as surrogates for replacement and interstitial fibrosis respectively. New conduction abnormalities were defined by the presence of transient or permanent atrioventricular block, new bundle branch blocks, and need for permanent pacemaker. Association of myocardial fibrosis and new conduction derangements were tested using receiver operator curve (ROC) and regression analysis in patients with and without pre-existing conduction issues. RESULTS: Forty-six (27.1%) patients developed post-TAVR conduction deficits. ECV was significantly higher among patients who experienced new conduction defects (26.2 ± 3.45% vs. 24.7% ± 4.15%, p value: 0.020). A greater fraction of patients that had new conduction defects had an elevated ECV of ≥26% (54.3% vs. 36.3%, p value: 0.026). ECV ≥ 26% was independently associated with the development of new conduction defects (odds ratio [OR]: 2.364, p value: 0.030). ROC analysis revealed a significant association of ECV with new conduction defects with an area under the receiver operating characteristic curve (AUC) of 0.632 (95% confidence interval: 0.555-0.705, p value: 0.005). The combination of prior right bundle branch block (RBBB) and ECV revealed a greater AUC of 0.779 (0.709-0.839, p value: <0.001) than RBBB alone (Delong p value: 0.049). No association of LGE/ECV with new conduction defects was observed among patients with pre-existing conduction disease. Among patients without baseline conduction disease, ECV was independently associated with the development of new conduction deficits (OR: 3.685, p value: 0.008). CONCLUSION: The present study explored the association of myocardial fibrosis, as measured by LGE and ECV with conduction deficits post-TAVR. Our results demonstrate an association of ECV, and thereby interstitial myocardial fibrosis, with new conduction derangement post-TAVR and introduce ECV as a potentially new risk stratification tool to identify patients at higher risk for needing post-TAVR surveillance and/or permanent pacemaker.

Nonpharmacologic rate control of postoperative atrial fibrillation in the canine sterile pericarditis model.

INTRODUCTION: Postoperative atrial fibrillation (POAF) is common following open heart surgery, and is associated with significant morbidity. Medications used for ventricular rate control of POAF may not be effective in controlling rapid ventricular rates during the postoperative period because of increased sympathetic tone. The purpose of this study was to develop nonpharmacologic rate control of POAF by atrioventricular node (AVN) fat pad stimulation using clinically available temporary pacing wires in the canine sterile pericarditis model. METHODS: We studied 10 sterile pericarditis dogs in the closed-chest state on postoperative days 1-3. The AVN fat pad stimulation (amplitude 2-15 mA; frequency 20 Hz; pulse width 0.03-0.2 ms) was performed during sustained POAF (>5 min). We measured ventricular rate and inefficient ventricular contractions during sustained POAF and compared it with and without AVN fat pad stimulation. Also, the parameters of AVN fat pad stimulation to achieve a rate control of POAF were measured over the postoperative days. RESULTS: Eleven episodes of sustained POAF were induced in 5/10 sterile pericarditis dogs in the closed-chest state on postoperative days 1-2. During POAF, the AVN fat pad stimulation decreased the ventricular rate from 178 ± 52 bpm to 100 ± 8 bpm in nine episodes. Nonpharmacologic rate control therapy successfully controlled the ventricular rate and eliminated inefficient ventricular contractions during POAF for the duration of the AVN fat pad stimulation. The AVN fat pad stimulation output remained relatively stable over the postoperative days. CONCLUSION: During sustained POAF, nonpharmacologic rate control by AVN fat pad stimulation effectively and safely controlled rapid ventricular rates throughout the postoperative period.

Permanent Pacemaker Insertion Reduction and Optimized Temporary Pacemaker Management After Contemporary Transcatheter Aortic Valve Implantation With Self-Expanding Valves (from the Pristine TAVI Study).

Permanent pacemaker implantation (PPMI) reduction and optimal management of newly acquired conduction disturbances after transcatheter aortic valve implantation (TAVI) are crucial. We sought to evaluate the relation between transcatheter heart valve (THV) implantation depth and baseline and newly acquired conduction disturbances on PPMI after TAVI. This study included 1,026 consecutive patients with severe symptomatic aortic stenosis (mean age 79.7 ± 8.4 years; 47.4% female) who underwent TAVI with the newer-generation self-expanding THVs Primary outcomes were early and late PPMI defined as the need for PPMI during the index admission and between discharge and 30 days, respectively. Early and late PPMI was required for 115 (11.2%) and 21 patients (2.0%), respectively. Early PPMI rates decreased from 26.7% in 2015 and 2016 to 5.7% in 2021, and so did the mean THV depth from 4.4 ± 2.4 mm to 1.8 ± 1.6 mm. Receiver operator characteristics curve analyses showed THV depth had significant discriminatory value for early and late PPMI with cutoff values of 3.0 and 2.2 mm, respectively. Rates of early and late PPMI were significantly lower for patients with shallower compared with deeper implantations (5.1% vs 22.6% and 0.4% vs 4.1%, p <0.001 for both, respectively). Furthermore, rates of early PPMI were lower with shallower implantations in patients with new left bundle branch block after TAVI (2.4% vs 15.9%; p <0.001) and those with baseline right bundle branch block (7.5% vs 29.6%; p = 0.017). Lower rates of PPMI with shallower THV implantation were consistently observed, including in patients with baseline and newly acquired conduction disturbances. Our findings might help optimize the management of a temporary pacemaker after TAVI.

The Evolving Burden of Drug Use Associated Infective Endocarditis in the United States.

BACKGROUND: The rise in the number of valve operations performed for infective endocarditis (IE) due to drug use is an important manifestation of the opioid epidemic. This study characterized national trends and outcomes of valve surgery for drug use-associated IE (DU-IE). METHODS: Adults undergoing valve surgery for active IE in The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database between July 2011 and June 2018 were stratified as DU-IE and non-DU-IE. Trends and clinical profiles were analyzed. Early outcomes were assessed. The association of DU-IE with outcomes was analyzed with multivariable regression, adjusting for STS Valve Risk model covariates. RESULTS: There were 34,905 valve operations performed for IE, of which 33.7% were for DU-IE. DU-IE operations increased 2.7-fold during the study period. There was considerable regional variability in DU-IE operations, ranging from 28% to 58% of all IE surgeries in 2018, with highest rates observed in East South Central and South Atlantic regions. DU-IE patients were younger and had fewer cardiovascular comorbidities. Risk-adjusted major morbidity and in-hospital mortality were significantly higher in the DU-IE group. Redo valve procedures in DU-IE patients were associated with worse outcomes, compared with those receiving a first valve operation. CONCLUSIONS: Operations for DU-IE have increased sharply in the United States during the last several years, exhibiting substantial regional variability. DU-IE patients have unique clinical profiles, and worse risk-adjusted outcomes. This demonstrates the significant impact of the opioid epidemic on endocarditis surgeries and punctuates the urgent need for multidisciplinary regional and national efforts to reverse this trend.

Faculty Development: Using Education for Career Advancement.

Faculty development is important at any level of academic rank but is especially important in early stages. The clinical educator is a rewarding pathway that is emerging as a special track for promotion and advancement. Success is achievable through development of skills, measurement of progress, obtaining funding, and completion of projects through publication. Advanced degrees, mentorship, and persistence are keys to achievement.

Surgical Mapping and Ablation in the Left Ventricular Summit Guided by Presurgery Pericardial Mapping.

Successful catheter ablation of ventricular arrhythmias arising from the left ventricular (LV) summit is challenging. The use of a catheter-based epicardial approach may be limited due to the proximity of the major coronary arteries and the presence of epicardial fat. Surgical cryoablation in the LV summit is a viable option for drug-refractory ventricular arrhythmias. Presurgical epicardial mapping can facilitate the surgical procedure by localizing the area of interest to allow for a more limited surgical dissection of the epicardial fat.

Aortic Dysfunction in Mitral Regurgitation Due to Floppy Mitral Valve/Mitral Valve Prolapse.

BACKGROUND: Floppy mitral valve/mitral valve prolapse (FMV/MVP), a heritable disorder of connective tissue, often leads to mitral regurgitation (MR) and is the most common cause for mitral valve surgery in developed countries. Connective tissue disorders may affect aortic function, and a stiff aorta may increase the severity of MR. Aortic function, however, has not been studied in FMV/MVP with MR. METHODS: A total of 17 patients (11 men, 6 women) with FMV/MVP and significant MR were compared with 20 controls matched for age and gender. Aortic diameters (AoD) were measured from left ventriculograms at 2 and 4 cm above the aortic valve. Aortic pressures were measured directly using fluid-filled catheters. Aortic distensibility was calculated using the formula: 2(systolic AoD-diastolic AoD)/(diastolic AoD x pulse pressure). RESULTS: Aortic distensibility was significantly lower in FMV/MVP compared with control at 2 cm above the aortic valve (1.00 ± 0.19 versus 3.78 ± 1.10 10-3 mm Hg-1, respectively; p = 0.027) and 4 cm above the aortic valve (0.89 ± 0.16 versus 3.22 ± 0.19 10-3 mm Hg-1, respectively; p = 0.007). FMV/MVP patients had greater left ventricular (LV) end-systolic (88 ± 72 mL versus 35 ± 15 mL, p = 0.002) and end-diastolic (165 ± 89 mL versus 100 ± 41 mL, p = 0.005) volumes, and lower LV ejection fraction, compared with control (50 ± 12% versus 57 ± 6%, p = 0.034). CONCLUSION: Aortic distensibility is decreased (consistent with a stiff aorta) in patients with FMV/MVP and MR. A stiff aorta may increase the severity of MR. Thus, abnormal aortic function, which also deteriorates with age, may play an important role in the natural history of MR due to FMV/MVP.

Vascular Assessment for Transcatheter Aortic Valve Replacement: Intravascular Ultrasound Compared With Computed Tomography.

BACKGROUND: Assessment of the femoral and iliac arteries is essential prior to transcatheter aortic valve replacement (TAVR). It is critical for establishing candidacy for a femoral approach, and can help predict vascular complications. Although computed tomography angiography (CTA) is the standard imaging modality, it has limitations. OBJECTIVE: This study compared CTA with intravascular ultrasound (IVUS) in patients undergoing TAVR evaluation. METHODS: Fifteen patients undergoing pre-TAVR coronary angiography and hemodynamic assessment were recruited. Following coronary angiography, patients underwent distal aortography, bilateral iliac and femoral arteriography, and IVUS assessment. Vascular tortuosity, minimum lumen diameter, and cross-sectional area were obtained and the findings were compared with those obtained from CTA. RESULTS: Correlation between IVUS and CTA was strong for minimum luminal diameter (r=0.62). Concordance was also strong between CTA and invasive iliofemoral angiography for assessment of tortuosity (r=0.75). Utilizing Bland-Altman analysis, vessel diameters obtained by IVUS were consistently greater than those obtained by CTA. The angiography and IVUS strategy was associated with a lower overall mean contrast utilization (29 cc vs 100 cc; P<.001), reduced mean radiation exposure (527 mGy vs 998 mGy; P=.045), and no significant difference in mean test duration (13.3 minutes vs 10 minutes; P=.12). CONCLUSIONS: For femoral and iliac arterial assessment prior to TAVR, IVUS is a viable alternative to CTA with comparable accuracy, and the potential for less contrast use and less radiation exposure. IVUS is also a valuable adjunct to CTA in patients with borderline femoral access diameters or considerable CTA artifacts.

Modifications, classification, and outcomes of elephant-trunk procedures.

BACKGROUND: There are a variety of modified elephant-trunk methods, including use of endovascular stents. Our objectives were to classify these modifications, compare outcomes between the classic anastomotic site and these alternatives, and investigate time to second-stage elephant-trunk completion. METHODS: From May 1992 to January 2011, 526 patients underwent a first-stage elephant-trunk procedure and were the subject of analysis. RESULTS: Distal aortic anastomosis was located before the brachiocephalic artery in 6 patients (1.1%), between brachiocephalic and left common carotid artery (LCCA) in 1 (0.19%), between LCCA and left subclavian artery (LSCA) in 154 (29%), and beyond the LSCA (classic) in 365 (69%). Stroke occurred in 8% (n = 42) overall, 10% (n = 16) in the LCCA-LSCA group, and 6.8% (n = 25) in the classic group. Risk factors were older age and acute dissection. Thirty-day mortality was 7.6% (n = 40) and was similar for LCCA-LSCA (9.7%) and classic sites (6.3%; p = 0.7); risk factors included older age, smaller body surface area, and end-organ dysfunction. Likelihood of death before second-stage elephant trunk at 1, 4, and 8 years after operation was 16%, 22%, and 27%, respectively. The larger the distal aorta, the more likely was second-stage completion (p < 0.0001); when greater than 6 cm, 80% had second-stage completion. CONCLUSIONS: The elephant-trunk operation is safe for a broad population, including when anastomotic sites are other than beyond the LSCA. Without second-stage completion, patient mortality increases markedly after 4 years.

Thoracic outlet syndrome caused by fibrous dysplasia of the first rib.

Fibrous dysplasia causing thoracic outlet syndrome is rare. A 41-year-old woman presented with neurogenic thoracic outlet syndrome with imaging that demonstrated a large tumor of her proximal left first rib. Transaxillary excision was unsuccessful due to involvement of the subclavian vasculature and brachial plexus. Subsequent posterolateral thoracotomy and resection of her first rib revealed fibrous dysplasia. Thoracotomy should be considered in these cases for optimal vascular control and identification of thoracic outlet anatomy.