Citations

Background: Conduction abnormality post-transcatheter aortic valve implantation (TAVI) remains clinically significant and usually requires chronic pacing. The effect of right ventricular (RV) pacing post-TAVI on clinical outcomes warrants further studies. Methods: We identified 147 consecutive patients who required chronic RV pacing after a successful TAVI procedure and propensity-matched these patients according to the Society of Thoracic Surgeons (STS) risk score to a control group of patients that did not require RV pacing post-TAVI. We evaluated routine echocardiographic measurements and performed offline speckle-tracking strain analysis for the purpose of this study on transthoracic echocardiographic (TTE) images performed at 9 to 18 months post-TAVI. Results: The final study population comprised 294 patients (pacing group n = 147 and non-pacing group n = 147), with a mean age of 81 ± 7 years, 59% male; median follow-up was 354 days. There were more baseline conduction abnormalities in the pacing group compared to the non-pacing group (56.5% vs. 41.5%. p = 0.01). Eighty-eight patients (61.6%) in the pacing group required RV pacing due to atrioventricular (AV) conduction block post-TAVI. The mean RV pacing burden was 44% in the pacing group. Left ventricular ejection fraction (LVEF) was similar at follow-up in the pacing vs. non-pacing groups (57 ± 13.0%, 59 ± 11% p = 0.31); however, LV global longitudinal strain (−12.7 ± 3.5% vs. −18.8 ± 2.7%, p < 0.0001), LV apical strain (−12.9 ± 5.5% vs. 23.2 ± 9.2%, p < 0.0001), and mid-LV strain (−12.7 ± 4.6% vs. −18.7 ± 3.4%, p < 0.0001) were significantly worse in the pacing vs. non-pacing groups. Conclusions: Chronic RV pacing after the TAVI procedure is associated with subclinical LV systolic dysfunction within 1.5 years of follow-up.

Abstract The scaphotrapeziotrapezoid (STT) joint is involved in load transmission between the wrist and thumb. A quantitative description of baseline STT joint morphometrics is needed to capture the variation of normal anatomy as well as to guide staging of osteoarthritis. Statistical shape modeling (SSM) techniques quantify variations in three‐dimensional shapes and relative positions. The objectives of this study are to describe the morphology of the STT joint using a multi‐domain SSM. We asked: (1) What are the dominant modes of variation that impact bone and articulation morphology at the STT joint, and (2) what are the morphometrics of SSM‐generated STT joints? Thirty adult participants were recruited to a computed tomography study of normal wrist imaging and biomechanics. Segmentations of the carpus were converted to three‐dimensional triangular surface meshes. A multi‐domain, particle‐based entropy system SSM was used to quantify variation in carpal bone shape and position as well as articulation morphology. Articular surface areas and interosseous proximity distributions were calculated between mesh vertex pairs on adjacent bones within distance (2.0 mm) and surface‐normal angular (35°) thresholds. In the SSM, the first five modes of variation captured 76.2% of shape variation and contributed to factors such as bone scale, articular geometries, and carpal tilt. Median interosseous proximities—a proxy for joint space—were 1.39 mm (scaphotrapezium), 1.42 mm (scaphotrapezoid), and 0.61 mm (trapeziotrapezoid). This study quantifies morphological and articular variations at the STT joint, presenting a range of normative anatomy. The range of estimated interosseous proximities may guide interpretation of imaging‐derived STT joint space.

Background: The compensatory reserve metric (CRM) provides a novel marker of hemodynamic status in prediction of sudden cardiovascular decompensation during central hypovolemia. The CRM has previously been calculated using arterial waveforms obtained from a photoplethysmographic volume-clamp technique. However, the in-field use of pulse oximetry is becoming more prominent in research and medicine. To improve in-field applicability of the CRM, this project aimed to validate pulse-oximetry derived CRM values relative to physiologic data during simulated hemorrhage through application of lower body negative pressure (LBNP). Methods: Forty-nine healthy adults (25 females) underwent a graded LBNP protocol with the following 5-minute stages: -0, -15, -30, -45, -60, -70, -80, -90, and 100 mmHg, or until the onset of pre-syncopal symptoms (tolerance) was reached. Arterial waveforms were sampled using pulse oximetry (Massimo Radical 7). The CRM was calculated using a validated one-dimensional convolutional neural network. A brachial artery catheter was used to measure intraarterial pressure. A 3-lead ECG was used to measure heart rate. SpO2 was measured using pulse oximetry. Cardiac output and stroke volume were estimated using the photoplethysmographic volume-clamp. Data were binned for the last thirty seconds of each completed stage, and at tolerance. Fixed-effect linear mixed models with repeated measures were used to examine the association between CRM values and physiologic variables. A priori significance was set at P<0.05. Results: The median LBNP stage reached was 70 mmHg (Range: 45-100 mmHg). Relative to baseline, at tolerance there was a 50±12% ( P<0.001) mean reduction in stroke volume, 65±27% ( P<0.001) increase in heart rate, 18±8% ( P<0.001) reduction in mean arterial pressure, 21±7% ( P<0.001) systolic blood pressure, 8±9% ( P<0.001) diastolic blood pressure, and 39±12% ( P<0.001) pulse pressure. The CRM obtained using pulse oximetry was significantly associated with a reduction in stroke volume ( P<0.001), increase in heart rate ( P<0.001), and reductions in systolic ( P=0.033), diastolic ( P=0.036), and pulse pressure ( P=0.002). There was no statistically significant association between CRM and cardiac output ( P=0.421), SpO2 ( P=0.408), or mean arterial pressure ( P=0.214). Conclusion: The CRM obtained using pulse oximetry may be a valid, reliable marker of hemodynamic status with promising in-field applications. Future studies warrant investigation of feasibility and applicability within various contexts ranging from the operating room to the battlefield. The presented work was funded in part by the Congressionally Directed Medical Research Program (Award No. DM180240) and Offce of Naval Research (Awards No. N00014-18-D-7001 and N00014-19-C-2017). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

ABSTRACT Phage therapy has not been established in the clinical routine, in part due to uncertainties concerning efficacy and immunogenicity. Here, three rabbits were immunized against staphylococcal phage K to assess viral potency in the presence of immunized serum. Three rabbits received weekly intramuscular injections of ~10 10±1 pfu/mL phage K. Phage K-specific IgG formation was measured by an enzyme-linked immunosorbent assay (ELISA); phage inactivation was assessed by calculating K-rates. Using transmission electron microscopy (TEM) and immunogold labeling, antibody binding to phage K was visualized. This was numerically assessed by objective imaging analysis comparing the relative distances of each gold particle to the nearest phage head and tail structure. Immunization led to a strong IgG response, plateauing 7 days after the last phage injection. There was no significant correlation between K-rate and antibody titer over time. TEM showed IgG binding to the head structure of phage K. Image analysis showed a significant reduction in relative distances between antibodies and phage head structures when comparing samples from day 0 and day 28 ( P < 0.0001). These results suggest that while individual serum analysis for antibodies against therapeutic phage bears consideration prior to and with prolonged therapy, during phage application, the formation of specific antibodies against phage may only partially explain decreased phage potency in the presence of immunized serum. Instead, other factors may contribute to an individual’s “humoral receptiveness” to phage therapy. Future investigations should be directed toward the identification of the humoral factors that have the most significant predictive value on phage potency in vivo .

Abstract Aims Doppler mean gradient (MG) can underestimate aortic stenosis (AS) severity in patients with atrial fibrillation (AF) compared with patients with sinus rhythm (SR), potentially delaying intervention in AF. This study compared outcomes in patients with AF and SR following transcatheter aortic valve replacement (TAVR) and investigated delay in TAVR based on computed tomography aortic valve calcium score (AVCS). Methods and results Patients who underwent TAVR from 2013 to 2017 for native valve severe AS were identified from an institutional database. Baseline characteristics and overall survival were compared between those with SR and AF. There were 820 patients (mean age 81 years; 41.6% females) included in this study. AF was present in 356 patients. Patients with AF were older (82.2 vs. 80.5, P = 0.003) and had a lower MG compared with patients with SR (42.0 vs. 44.9, P = 0.002) with similar indexed aortic valve area (0.4 vs. 0.4, P = 0.17). Median AVCS was higher in AF (males: AF 2850.0 vs. SR 2561.0, P = 0.044; females: AF 1942.0 vs. SR 1610.5, P = 0.025). Projected AVCS, assuming the same age of diagnosis, was similar between AF and SR. Median survival post-TAVR was worse in AF compared with SR (3.2 vs. 5.4 years, log rank P &lt; 0.001). AF, lower MG, higher right ventricular systolic pressure, dialysis, diabetes, and significant tricuspid regurgitation were associated with higher mortality (P &lt; 0.05 for all). Conclusion Older age and higher AVCS in patients with AF compared with those with SR suggest that AS was both underestimated and more advanced at TAVR referral.

Introduction: Left atrial appendage closure (LAAC) device for stroke prevention is a safe and effective alternative to oral anticoagulation (OAC) in patients with atrial fibrillation (AF). The safety of performing LAAC on uninterrupted warfarin (UW) compared to interrupted warfarin (IW) is currently unknown. Hypothesis: Complication rates of performing LAAC on UW vs. IW will be similar. Methods: We reviewed the data from the second half of PROTECT-AF trial, PREVAIL trial, CAP and CAP2 registries. Patients were categorized to the UW group if INR on the day of the procedure was ≥2 and to the IW group if INR was <2. Procedural complications within 7 days of LAAC were reviewed. An association between complications and AC strategy was analyzed. Results: Data from 1580 patients were reviewed and 294 patients (18.6%) received LAAC on UW. The UW group had a mean INR of 2.4±0.4 and IW group had a mean INR of 1.3±0.3. There were several differences in baseline characteristics: lower BMI in the UW group (28.6±5.3 vs 29.5±6.0, p=0.01), fewer patients with hypertension in the UW group (87.1% vs 91.1%, p=0.04), lower HAS-BLED score in the UW group (2.0±1.0 vs 2.1±1.0, p<0.01), and more patients with persistent AF in the UW group (37.1% vs 26.4%, p<0.01). Overall, there were no significant differences in total or individual complication rates between the two groups (UW 5.1% vs IW 6.1%, p=0.59). Although not statistically significant, lower event rates were noted in the UW group for the following: stroke (0% vs 0.3%, p>0.99), pericardial effusion requiring intervention (1.7% vs 1.8%, p>0.99), pseudoaneurysm (0% vs 0.4%, p=0.59), hematoma (0% vs 0.2%, p>0.99), and device embolism (0% vs 0.2%, p=1.0). The UW group had statistically insignificant higher events rates of AV fistula (0.3% vs 0%, p=0.19) and major bleeding requiring transfusion (1% vs 0.5%, p=0.38). In addition, there was no significant difference in periprocedural ischemic stroke (0% vs 0.3%, p>0.99). Conclusion: In this retrospective analysis, no significant difference was observed in procedural complication rates when performing LAAC on UW vs. IW. These results suggest that LAAC can be safely performed without interruption of OAC.

Introduction: Atrial fibrillation (AF) is a serious complication, which occurs in 30% to 40% of patients after surgical aortic valve replacement (SAVR) and contributes to adverse outcomes. Advanced technology has enabled transcatheter aortic valve replacement (TAVR) in patients with High-risk Severe Aortic Stenosis (HRSAS). In these patients, the compliance of the systemic vasculature is an independent predictor of diastolic dysfunction, a known predictor of postoperative AF (POAF). We hypothesize that patients with HRSAS undergoing TAVR represent a population at increased risk for POAF. METHODS: The medical records of 195 TAVR patients at the Mayo Clinic from November 2008 to January 2013 were analyzed. All patient demographic, clinical, pre- and post-procedural outcomes were collected from the patients’ medical records, and reviewed to ascertain all cases of POAF (AF ≤30 days of surgery). Patients with a prior history of AF (n= 75 (38.5%)) were excluded. Logistic regression analysis was used to identify clinical predictors of POAF after TAVR. Results: The mean age of the study population was 80.8±7.8 years and 60.8% (n=73) were men. The mean STS risk score was 8.9±5.1. Of the 120 patients without prior AF, 20.8% (n=25) developed new-onset POAF after TAVR. Patients who developed POAF were more likely to have undergone a transapical or transaortic TAVR approach (OR 3.20; 95% CI (1.3-8.0), had a higher incidence of renal complications (52.0% vs 21.5%; p= 0.003), greater hospital length of stay (7.4±2.58 vs 5.0±2.6 days; p= 0.0003, and a trend toward higher 30-day mortality (28.0% vs 13.7%; p= 0.09) and pulmonary complications (16.0% vs 5.4%; p= 0.08) compared with those who did not develop POAF, respectively. Neurologic complications were not different between the 2 group (4.0% vs 3.2%; p= 0.85). Conclusions: Patients with High-risk Severe Aortic Stenosis undergoing TAVR have increased risk of POAF, primarily associated with a transapical or aortic surgical approach. Patients who develop POAF had higher incidence of post-procedural complications and longer hospitalizations. Therefore, perioperative strategies aimed at prevention of POAF are as important in TAVR patients as in those undergoing SAVR.

Background: Randomized clinical trials are often criticized for not reflecting real-world practice. To understand the effect of site and patient selection on trial generalizability, we examined US patient and hospital participation within the Dual Antiplatelet Therapy (DAPT) Study, a broadly inclusive trial of PCI patients, using a linked analysis with the CathPCI Registry®. Methods: Within the CathPCI Registry, we identified patients undergoing PCI between September 1, 2009 and July 1, 2011 - the period of DAPT Study enrollment. We compared US patients enrolled in DAPT to CathPCI Registry patients meeting DAPT inclusion criteria. Characteristics of US DAPT sites were also compared to those of hospitals not participating in DAPT. Standardized differences (%) for all variables were estimated, with those greater than 10% considered significant. Results: Among 1,139,932 NCDR patients undergoing PCI, 748374 (65.7%) met the enrollment criteria for DAPT, and 23495 (2.1%) were enrolled. Enrolled patients were younger and had lower rates of prior stroke, CHF and peripheral vascular disease, but were similar with respect to race and gender compared with eligible patients (Table). Of the 1276 hospitals within the NCDR, 309 (24.2%) participated in DAPT. Hospital characteristics differed markedly, with DAPT-participating hospitals being larger (mean beds 468 vs. 311), more often located in urban settings (61.2% vs. 42.6%), more often affiliated with training programs (53.7% vs. 34.1%), and with higher annual PCI volumes (mean annual hospital volume 858 vs. 378 PCIs) compared with non-DAPT hospitals. Conclusions: While liberal inclusion criteria may allow randomized trials to better simulate “real-world” clinical practice, the process of site selection may encourage participation of higher volume, urban hospital settings. These findings are relevant to clinical trial interpretation and implementation of evidence-based practice throughout the healthcare system.

Objective: To evaluate outcomes of acute spontaneous coronary artery dissection (SCAD) managed with percutaneous coronary intervention (PCI) or conservative therapy. Background: SCAD is a non-atherosclerotic acute coronary syndrome that typically affects young otherwise healthy females. Whether SCAD with normal vessel flow at presentation should be managed with PCI or conservative therapy remains unknown. Methods: We performed a retrospective study of patients after a first SCAD episode (n=142). We excluded those treated with fibrinolysis (n=12) or coronary artery bypass grafting (CABG, n=8). We evaluated in-hospital and late outcomes in three SCAD groups: Vessel occlusion at presentation treated with PCI (Occ-PCI, n=30); normal vessel flow treated with PCI (NF-PCI, n=34) and those managed conservatively (CON, n=58). Results: Overall mean age was 42+9 years, 91% were female and 41% presented with STEMI. Outcomes are shown in the table below. In Occ-PCI, technical failure occurred in 8/30 (27%), of whom 5 required emergency CABG with one in-hospital death. Comparing NF-PCI with CON, there were no differences in clinical characteristics. Technical failure occurred in 16/34 (47%) of NF-PCI due to failure to cross with wire/device (8/34) or final loss of flow (8/34). Emergency CABG was required in 5 (15%). In CON, 54/58 had an uneventful in-hospital course. Four (7%) exhibited early dissection progression of whom two received PCI and one CABG. Long-term rates of target vessel revascularization, but not recurrent SCAD, were higher in NF-PCI vs CON (26% vs 9%, p=0.02; 24% vs 14%, p=0.23). Conclusions: PCI for acute SCAD is associated with high rates of technical failure and adverse clinical outcomes. In SCAD with normal vessel flow, conservative management may be preferable, with close early observation due to a hazard of progression of dissection. These findings underscore the importance of tailoring therapy to etiology of coronary obstruction.