Sriram Nathan

PREVENtion of HeartMate II Pump Thrombosis Through Clinical Management: The PREVENT multi-center study

BACKGROUND Recommended structured clinical practices including implant technique, anti-coagulation strategy, and pump speed management (PREVENT [PREVENtion of HeartMate II Pump Thrombosis Through Clinical Management] recommendations) were developed to address risk of early (<3 months) pump thrombosis (PT) risk with HeartMate II (HMII; St. Jude Medical, Inc. [Thoratec Corporation], Pleasanton, CA). We prospectively assessed the HMII PT rate in the current era when participating centers adhered to the PREVENT recommendations. METHODS PREVENT was a prospective, multi-center, single-arm, non-randomized study of 300 patients implanted with HMII at 24 participating sites. Confirmed PT (any suspected PT confirmed visually and/or adjudicated by an independent assessor) was evaluated at 3 months (primary end-point) and at 6 months after implantation. RESULTS The population included 83% men (age 57 years ± 13), 78% destination therapy, and 83% Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Profile 1-3. Primary end-point analysis showed a confirmed PT of 2.9% at 3 months and 4.8% at 6 months. Adherence to key recommendations included 78% to surgical recommendations, 95% to heparin bridging, and 79% to pump speeds ≥9,000 RPMs (92% >8,600 RPMs). Full adherence to implant techniques, heparin bridging, and pump speeds ≥9,000 RPMs resulted in a significantly lower risk of PT (1.9% vs 8.9%; p < 0.01) and lower composite risk of suspected thrombosis, hemolysis, and ischemic stroke (5.7% vs 17.7%; p < 0.01) at 6 months. CONCLUSIONS Adoption of all components of a structured surgical implant technique and clinical management strategy (PREVENT recommendations) is associated with low rates of confirmed PT.

How do we manage cardiopulmonary bypass coagulopathy

Patients who undergo cardiopulmonary bypass (CPB) are at risk for coagulopathy. Suboptimal turnaround time (TAT) of laboratory coagulation testing results in empiric administration of blood products to treat massive bleeding. We describe our initiative in establishing the coagulation‐based hemotherapy (CBH) service, a clinical pathology consultation service that uses rapid TAT coagulation testing and provides comprehensive assessment of bleeding in patients undergoing CPB. A transfusion algorithm that treats the underlying cause of coagulopathy was developed.

Percutaneous ventricular assist device and extracorporeal membrane oxygenation support in a patient with postinfarction ventricular septal defect and free wall rupture.

We describe the case of a 54-year-old woman with a postinfarction ventricular septal defect (VSD) and ventricular free wall rupture who was stabilized with a percutaneous ventricular assist device (pVAD) to allow for myocardial infarct stabilization. Following the rupture of the right ventricular free wall and cardiopulmonary arrest on hospital day 10, pVAD support was promptly converted to extracorporeal membrane oxygenation (ECMO) support for stabilization. After surgical repair was completed, pVAD support was continued for 4 days to allow recovery. The patient was discharged on postoperative day 11 and is alive and well 4 years later. Postinfarction VSD with free wall rupture may be salvaged with pVAD and ECMO support.

Extracorporeal membrane oxygenation as a procedural rescue strategy for transcatheter Aortic valve replacement Cardiac Complications

Cardiovascular complications during or after transcatheter aortic valve replacement (TAVR) are associated with extremely high mortality, but extracorporeal membrane oxygenation (ECMO) can be used as procedural rescue option to improve outcomes when patients experience respiratory or cardiac arrest. From 2012 to 2014, 230 patients underwent TAVR and 10 patients (4.3%) required emergent venous-arterial ECMO support. Mean age was 83 years, median Society of Thoracic Surgeons (STS) score was 15, and mean aortic gradient was 45 mm Hg. Median left ventricular ejection fraction was 35%. Access for most ECMOs was femoral; two patients required central arterial and femoral venous access. Extracorporeal membrane oxygenation was initiated in response to hemodynamic collapse due to perforation of left ventricle (n = 2), aortic root rupture (n = 1), moderate-to-severe aortic insufficiency (n = 1), left main impingement (n = 1), valve embolization (n = 1), severe hypotension and cardiac arrest after prolonged rapid pacing sequence (n = 1), ventricular fibrillation (n = 2), and ventricular tachycardia (n = 1). Median time of ECMO support was 87 minutes. There were three hospital deaths. Post-TAVR mean aortic gradient was 8 mm Hg and median hospital stay was 19 days. Additional procedures included valve-in-valve placement (n = 1), percutaneous coronary intervention (n = 1), surgical LV repair (n = 2), surgical valve replacement (n = 1), aortic root rupture repair, and coronary bypass grafting (n = 1). Extracorporeal membrane oxygenation is rescue therapy for hemodynamic instable patients who develop TAVR-related cardiac complications.

Short-Term Experience with Off-Pump Versus On-Pump Implantation of the HeartWare Left Ventricular Assist Device

Implantation of left ventricular assist devices while avoiding cardiopulmonary bypass (CPB) may decrease bleeding and improve postoperative recovery. To understand the effectiveness of this approach, we reviewed the charts of 26 patients who underwent HeartWare left ventricular assist device (HVAD) implantation without use of CPB (off-CPB group) and 22 patients who had HVAD implanted with CPB (CPB group) with an emphasis on the 30 day postoperative period. Preoperatively, both groups had similar demographic, functional, and hemodynamic characteristics. Off-CPB patients had significantly shorter surgery times than CPB patients, 188.5 (161.5–213.3) min versus 265.0 (247.5–299.5) min, respectively; p < 0.001. Blood transfusion requirements during surgery and within the postoperative 48 hour period were significantly lower in the off-CPB group than in the CPB group (odds ratio: 5.9; 95% confidence interval: 1.1–31.1, p = 0.042). Compared with the CPB group, the off-CPB group patients had a shorter intubation time, 21 (17.4–48.5) hours versus 41 (20.6–258.4) hours; p = 0.042. Intensive care unit stay was 7.0 (4.75–13.5) days for off-CPB versus 10.0 (6.0–19.0) days for CPB (p = 0.256). The off-CPB approach allows HVAD to be implanted quickly with significantly less perioperative bleeding and transfusion requirements and facilitates postoperative rehabilitation.

Perioperative use of tandemheart percutaneous ventricular assist device in surgical repair of postinfarction ventricular septal defect

Mortality for patients presenting with acute myocardial infarction (AMI) complicated by ventricular septal defect (VSD) and cardiogenic shock is very high even with surgical repair. We report our experience regarding utilization of TandemHeart, a percutaneous ventricular assist device (pVAD) as an adjunct to the treatment of these patients. Retrospective case series study design included a total of 11 patients with post-AMI VSD and severe refractory cardiogenic shock who received pVAD support at our institution. Three patients underwent immediate surgical repair and received pVAD support for postcardiotomy cardiogenic shock for 2, 4, and 7 days, respectively. However, all three died. The other eight patients had pVAD implanted prior to surgical repair in order to rest the myocardium before operation. Hemodynamics improved immediately after pVAD placement, and after receiving pVAD support for 7 ± 3 days, they underwent surgical VSD repair. Their total pre- and post-surgical pVAD support was 14 ± 4 days. All eight survived 30 days postoperatively. At 6 months postsurgery overall survival rate was 75%. Our small series of these critically ill patients shows a trend toward better survival after immediate pVAD placement to stabilize the patient and allow for myocardial maturation before surgical VSD repair.

Mobile Computing Platform With Decision Support Modules for Hemotherapy

OBJECTIVES We describe the development of a mobile computing platform (MCP) with a decision support module (DSM) for patients in our coagulation-based hemotherapy service. METHODS The core of our MCP consists of a Microsoft Excel spreadsheet template used to gather and compute data on cardiopulmonary bypass (CPB) patients intraoperatively. The DSM is embedded into the Excel file, where the user would enter in laboratory results, and through our 45 embedded algorithms, recommendations for transfusion products would be displayed in the Excel file. RESULTS The DSM has helped decrease the time it takes to come to a transfusion recommendation, helps double-check recommendations, and is an excellent tool for teaching. Furthermore, the problems that occur with a paper system have been eliminated, and we are now able to access this information easily and reliably. CONCLUSIONS The development and implementation of our MCP system has greatly increased the productivity and efficiency of our hemotherapy service.

Prolonged venovenous extracorporeal membrane oxygenation in a patient with acute respiratory distress syndrome

A 30 year-old Hispanic man with no significant previous medical history presented with refractory hypoxemia after flu-like symptoms. Because of progressive hypoxemia despite appropriate ventilator strategies, venovenous extracorporeal membrane oxygenation (VV-ECMO) was initiated for severe acute respiratory distress syndrome (ARDS). His course was complicated at our hospital by subarachnoid hemorrhage, right ventricular failure, multiple pneumothoraces, and significant deconditioning. He was able to be weaned off VV-ECMO after 193 days and was ambulatory at discharge from the hospital.

Primary cardiac sarcoidosis with syncope and refractory atrial arrhythmia: A case report and review of the literature

We discuss the case of a 38-year-old black man who presented at our hospital with his first episode of syncope, recently developed atrial arrhythmias refractory to pharmacologic therapy, and a left atrial thrombus. He was diagnosed with primary cardiac sarcoidosis characterized by predominant involvement of the epicardium that caused atrial fibrillation and atrial flutter. Histologic analysis of his epicardial lesions yielded a diagnosis of sarcoidosis. This patients atrial arrhythmia was successfully treated with a hybrid operation that involved resection of his atrial appendage, an Epicor maze procedure, and radiofrequency ablation during a catheter-based electrophysiologic study. The cardiac sarcoidosis was successfully managed with corticosteroid therapy. Our case report shows that sarcoidosis can initially manifest itself as syncope with new-onset atrial arrhythmia. Sarcoidosis is important in the differential diagnosis because of its progressive nature and its potential for treatment with pharmacologic, surgical, and catheter-based interventions.

A pseudo‐outbreak of disseminated cryptococcal disease after orthotopic heart transplantation

Cryptococcal infection is the third most common invasive fungal infection (IFI) among solid‐organ transplant (SOT) recipients and is considered an important opportunistic infection due to its significant morbidity and mortality. To determine whether a cluster of cryptococcosis in heart transplant patients was of nosocomial nature, three cases of orthotopic heart transplant recipients with postoperative disseminated cryptococcal infection were investigated and paired with an environmental survey in a tertiary care hospital. The infection prevention department conducted a multidisciplinary investigation, which did not demonstrate any evidence of health care‐associated environmental exposure. Moreover, multilocus sequence typing showed that one isolate was unique and the two others, although identical, were not temporally related and belong to the most common type seen in the Southern US. Additionally, all three patients had preexisting abnormalities of the CT chest scan and various degrees of acute and chronic rejection. Reactivation was suggested in all three patients. Screening methods may be useful to identify at risk patients and trigger a prophylactic or preemptive approach. However, more data is needed.