Sandhu, Gurpreet S.

AbstractObjectivesThe purpose of this study was to explore the feasibility and safety of robotic PCI performed using an off‐siteremote‐control system in an animal model.BackgroundAccess to primary percutaneous coronary intervention (PCI) remains a challenge in acute myocardial infarction management. The combination of telemedicine and robotic PCI allow the potential delivery of primary PCI to remote locations without the delay of transfer.MethodsThis single‐center prospective pilot preclinical feasibility study compared robotic PCI with remote PCI on swine across three stages (adjacent room, different floor of the same building, two different buildings). Latency up to 1,000 ms was introduced into the operating environment to simulate decreased network quality (blinded to operator). The primary outcome measures were technical success and acute safety. The secondary outcome measures included lesion wiring time, procedural time and qualitative scoring of the PCI experience by the operator.ResultsAcross 52 experiments in 15 animals, technical success was 100%. No procedural complications occurred during the study. No significant difference in lesion treatment time was detected between stages (p = .11) and between time per target vessel when latency up to 1,000 ms was introduced (p = .58). Injected delay >250 ms had the greatest impact on procedure perceived lag. Longer procedure time was associated with lower procedure impact score, regardless of injected latency.ConclusionsRemote robotic PCI was feasible and safe in an animal model. Procedural duration was acceptable and unaffected by network latency. Future studies are needed to determine the safety and feasibility of remote PCI in humans.

Abstract: Transcatheter aortic valve replacement is a relatively recent revolutionary treatment that has now become a standard procedure for treating severe aortic stenosis. In this article, the authors review the clinical history of transcatheter aortic valve replacement, summarize the major clinical trials, and describe the evolution of the technique over time. In doing so, the authors hope to provide a clear and concise review of the history and clinical evidence behind transcatheter aortic valve replacement.

Background: There are limited data on complications in acute myocardial infarction (AMI) admissions receiving extracorporeal membrane oxygenation (ECMO). Methods: Adult (>18 years) admissions with AMI receiving ECMO support were identified from the National Inpatient Sample database between 2000 and 2016. Complications were classified as vascular, lower limb amputation, hematologic, and neurologic. Outcomes of interest included temporal trends, in-hospital mortality, hospitalization costs, and length of stay. Results: In this 17-year period, in ~10 million AMI admissions, ECMO support was used in 4608 admissions (<0.01%)—mean age 59.5 ± 11.0 years, 75.7% men, 58.9% white race. Median time to ECMO placement was 1 (interquartile range [IQR] 0–3) day. Complications were noted in 2571 (55.8%) admissions—vascular 6.1%, lower limb amputations 1.1%, hematologic 49.3%, and neurologic 9.9%. There was a steady increase in overall complications during the study period (21.1% in 2000 vs. 70.5% in 2016). The cohort with complications, compared to those without complications, had comparable adjusted in-hospital mortality (60.7% vs. 54.0%; adjusted odds ratio 0.89 [95% confidence interval 0.77–1.02]; p = 0.10) but longer median hospital stay (12 [IQR 5–24] vs. 7 [IQR 3–21] days), higher median hospitalization costs ($458,954 [IQR 260,522–737,871] vs. 302,255 [IQR 173,033–623,660]), fewer discharges to home (14.7% vs. 17.9%), and higher discharges to skilled nursing facilities (44.1% vs. 33.9%) (all p < 0.001). Conclusions: Over half of all AMI admissions receiving ECMO support develop one or more severe complications. Complications were associated with higher resource utilization during and after the index hospitalization.

Background: Transcatheter mitral valve replacement using aortic transcatheter heart valves has recently become an alternative for patients with degenerated mitral bioprostheses, failed surgical repairs with annuloplasty rings or severe mitral annular calcification who are poor surgical candidates. Outcomes of these procedures are collected in the Society of Thoracic Surgeons/American College of Cardiology/Transcatheter Valve Therapy Registry. A comprehensive analysis of mitral valve-in-valve (MViV), mitral valve-in-ring (MViR), and valve-in-mitral annular calcification (ViMAC) outcomes has not been performed. We sought to evaluate short-term outcomes of early experience with MViV, MViR, and ViMAC in the United States. Methods: Retrospective analysis of data from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry. Results: Nine hundred three high-risk patients (median Society of Thoracic Surgeons score 10%) underwent MViV (n=680), MViR (n=123), or ViMAC (n=100) between March 2013 and June 2017 at 172 hospitals. Median age was 75 years, 59.2% female. Technical and procedural success were higher in MViV. Left ventricular outflow tract obstruction occurred more frequently with ViMAC (ViMAC=10%, MViR=4.9%, MViV=0.7%; P <0.001). In-hospital mortality (MViV=6.3%, MViR=9%, ViMAC=18%; P =0.004) and 30-day mortality (MViV=8.1%, MViR=11.5%, ViMAC=21.8%; P =0.003) were higher in ViMAC. At 30-day follow-up, median mean mitral valve gradient was 7 mm Hg, most patients (96.7%) had mitral regurgitation grade ≤1 (+) and were in New York Heart Association class I to II (81.7%). Conclusions: MViV using aortic balloon-expandable transcatheter heart valves is associated with a low complication rate, a 30-day mortality lower than predicted by the Society of Thoracic Surgeons score, and superior short-term outcomes than MViR and ViMAC. At 30 days, patients in all groups experienced improvement of symptoms, and valve performance remained stable. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02245763.

Background: Mechanical injury in the conduction system requiring permanent pacemaker (PPM) associated with transcatheter aortic valve replacement (TAVR) procedure is a common complication. The objective of this study was to use ambulatory monitor BodyGuardian to assess late occurrence of atrioventricular block (AVB) after TAVR. Methods: This prospective study evaluated 365 patients who underwent TAVR at Mayo Clinic, Rochester, Minnesota between June 2016 and August 2017. Patients who received PPM for bradycardia after TAVR before discharge were considered as the PPM group. Those not requiring PPM received a BodyGuardian system (BodyGuardian group) for 30 days of continuous monitoring. Primary end point was Mobitz II or third-degree atrioventricular block (II/III AVB) at 30-day follow-up. Results: Of 365 patients, 74 who had a PPM or an implantable cardioverter-defibrillator before TAVR and 94 who were enrolled in other studies were excluded. Of 197 patients enrolled in the study, 70 (35.5%) received PPM and 127 had BodyGuardian before the hospital dismissal. Eleven of 127 (8.6%) BodyGuardian group required PPM within 30 days after TAVR for late occurrence of symptomatic bradycardia. In total, 33 of 197 (16.7%) patients developed II/III AVB (24 before and 9 after discharge). Thirty-four patients had preexisting right bundle branch block. Of them, 16 (47%) developed II/III AVB. Of 53 patients who developed new left bundle branch block after TAVR, 14% progressed to II/III AVB within 30 days. Conclusions: In patients without a standard post-TAVR pacing indication, yet a potential risk to develop AVB, a strategy of 30-day monitoring identifies additional patients who require permanent pacing.

Background: Extracorporeal membrane oxygenation (ECMO) is increasingly used in acute myocardial infarction (AMI); however, there are limited large-scale national data. Methods: Using the National Inpatient Sample database from 2000 to 2014, a retrospective cohort of AMI utilizing ECMO was identified. Use of percutaneous coronary intervention, intra-aortic balloon pump, and percutaneous left ventricular assist device (LVAD) was also identified in this population. Outcomes of interest included temporal trends in utilization of ECMO alone and with concomitant procedures (percutaneous coronary intervention, intra-aortic balloon pump, and percutaneous LVAD), in-hospital mortality, and resource utilization. Results: In ≈9 million AMI admissions, ECMO was used in 2962 (<0.01%) and implanted a median of 1 day after admission. ECMO was used in 0.5% and 0.3% AMI admissions complicated by cardiogenic shock and cardiac arrest, respectively. ECMO was used more commonly in admissions that were younger, nonwhite, and with less comorbidity. ECMO use was 11× higher in 2014 as compared with 2000 (odds ratio, 11.37 [95% CI, 7.20–17.97]). Same-day percutaneous coronary intervention was performed in 23.1%; intra-aortic balloon pump/percutaneous LVAD was used in 57.9%, of which 30.3% were placed concomitantly. In-hospital mortality with ECMO was 59.2% overall but decreased from 100% (2000) to 45.1% (2014). Durable LVAD and cardiac transplantation were performed in 11.7% as an exit strategy. Of the hospital survivors, 40.8% were discharged to skilled nursing facilities. Older age, male sex, nonwhite race, and lower socioeconomic status were independently associated with higher in-hospital mortality with ECMO use. Conclusions: In AMI admissions, a steady increase was noted in the utilization of ECMO alone and with concomitant procedures (percutaneous coronary intervention, intra-aortic balloon pump, and percutaneous LVAD). In-hospital mortality remained high in AMI admissions treated with ECMO.

Abstract Abstract 4319 C-type natriuretic peptide (CNP) is known to exert pleiotropic effects on a variety of cell types through binding to its receptor, natriuretic peptide receptor type B (NPR-B) and activation of the cytoplasmic intracellular guanylyl cyclase domain. Although nitric oxide-mediated activation of cyclic guanosine monophosphate (cGMP) is known to induce megakaryocyte apoptosis and regulate platelet activation, the effects of CNP on these cells is yet to be defined. In this study for the first time we have addressed the potential role of CNP and NPR-B in megakaryocyte and platelet biology. We identified NPR-B on murine megakaryocytes by immunostaining demonstrating co-localization of CD41 and NPR-B. CNP induced cGMP production in megakaryocytes compared to a mutant form of CNP containing a single amino acid substitution (Lbab) (67.24 ± 10.65 fmol/well vs. 17.18 ± 2.089 fmol/well; P<0.05). Subsequently, CNP was shown to reduce megakaryocyte colony formation compared to Lbab and this effect was dose-dependent: Lbab 500nM 26.75 ± 5.618 CFU-M vs. 15.25 ± 2.750 CFU-M for CNP 500nM and Lbab 1000 nM 27.50 ± 2.102 CFU-M vs. 12.25 ± 1.493 CFU-M for CNP 1000nM; P<0.05). Furthermore, CNP also resulted in smaller-sized colonies, with altered cell morphology. To verify these findings, wild-type C57/BL6 mice were treated with daily injections of either saline, 1uM CNP or 1uM Lbab for one week, following which megakaryocytes were isolated and cultured. Colony formation was diminished in mice injected with CNP compared to mice receiving saline or Lbab peptide (125.3 ± 18.54 CFU-M for saline; 107.0 CFU-M ± 20.04 for Lbab and 20.00 ± 3.674 CFU-M for CNP; P<0.05). In addition platelet numbers were measured in the aforementioned mice and the CNP treated mice had significantly lower platelet counts compared to the mice treated with Lbab (832.0 ± 13.19 ×103/ul for CNP vs. 778.0 ± 12.00 ×103/ul for Lbab; P<0.05). Taken together, these data indicate that CNP may play a role in the development, maturation and/or survival of megakaryocytes. Using flow cytometry we identified that 47% of CD41+ murine platelets co-express NPR-B. In addition, this expression of NPR-B was confirmed by immunocytostaining and western blotting in both human and murine platelets. Interestingly, despite the expression of NPR-B, and unlike megakaryocytes, CNP (similar to the mutant peptide) did not increase cGMP production in platelets (1.652 ± 0.016 fmol/well for CNP and 1.606 ± 0.01550 fmol/well for Lbab). Further, although preliminary results did not indicate that CNP alters platelet secretion or aggregation, exposure to the peptide profoundly inhibited adhesion of platelets to collagen (53 ± 5 adhered platelets with Lbab, 32 ± 3 with CNP, relative reduction 42%; P<0.05). In summary, these results provide for the first time evidence that the NPR-B receptor is expressed on both megakaryocytes and platelets. Our studies suggest that CNP might have both cGMP dependent and independent functions in megakaryocytes and platelets and further studies will assist in delineating the mechanisms by which CNP exerts its actions on these cells. Disclosures: No relevant conflicts of interest to declare.

Background Patients with symptomatic severe aortic stenosis and a history of chest radiation therapy represent a complex and challenging cohort. It is unknown how transcatheter aortic valve replacement ( TAVR ) compares with surgical aortic valve replacement in this group of patients, which was the objective of this study. Methods and Results We retrospectively reviewed all patients with severe aortic stenosis who underwent either TAVR or surgical aortic valve replacement at our institution with a history of mediastinal radiation (n=55 per group). End points were echocardiographic and clinical outcomes in‐hospital, at 30 days, and at 1 year. Inverse propensity weighting analysis was used to account for intergroup baseline differences. TAVR patients had a higher STS score than surgical aortic valve replacement patients (5.1% [3.2, 7.7] versus 1.6% [0.8, 2.6], P <0.001) and more often ( P <0.01 for all) a history of atrial fibrillation (45.5% versus 12.7%), chronic lung disease (47.3% versus 7.3%), peripheral arterial disease (38.2% versus 7.3%), heart failure (58.2% versus 18.2%), and pacemaker therapy (23.6% versus 1.8%). Postoperative atrial fibrillation was less frequent (1.8% versus 27.3%; P <0.001) and hospital stay was shorter in TAVR patients (4.0 [2.0, 5.0] versus 6.0 [5.0, 8.0] days; P <0.001). The ratio of observed‐to‐expected 30‐day mortality was lower after TAVR as was 30‐day mortality in inverse propensity weighting–adjusted Kaplan–Meier analyses. Conclusions In patients with severe aortic stenosis and a history of chest radiation therapy, TAVR performs better than predicted along with less adjusted 30‐day all‐cause mortality, postoperative atrial fibrillation, and shorter hospitalization compared with surgical aortic valve replacement. These data support further studies on the preferred role of TAVR in this unique patient population.