Early Outcomes of the First 200 US Patients Treated with Impella 5.5: A Novel Temporary Left Ventricular Assist Device.

OBJECTIVE: To report the initial clinical experience with the Impella 5.5® with SmartAssist®, a temporary left ventricular assist device that provides up to 6.2 L/min forward flow, with recent FDA approval for up to 14 days. METHODS: From October 2019 to March 2020, 200 patients at 42 US centers received the Impella 5.5 and entered into the IQ registry, a manufacturer-maintained quality database that captures limited baseline/procedural characteristics and outcomes through device explant. Post hoc subgroup analyses were conducted to assess the role of baseline and procedural characteristics on survival, defined as successful device weaning or bridge to durable therapy. RESULTS: Median patient age was 62 years (range, 13 to 83 years); 83.4% were male. The device was most commonly used for cardiomyopathy (45.0%), acute myocardial infarction complicated by cardiogenic shock (AMICS; 29.0%), and post cardiotomy cardiogenic shock (PCCS; 16.5%). Median duration of support was 10.0 days (range, 0.001 to 64.4 days). Through device explant, overall survival was 74.0%, with survival of 80.0%, 67.2%, 57.6%, and 94.7% in cardiomyopathy, AMICS, PCCS, and others (comprising high-risk revascularization, coronary artery bypass graft, electrophysiology/ablation, and myocarditis), respectively. Patients requiring extracorporeal membrane oxygenation and Impella support (35 patients, 17.5%) had significantly lower survival (51.4% vs 78.8%, P = 0.002). CONCLUSIONS: In the first 200 US patients treated with the Impella 5.5, we observed overall survival to explant of 74%. Survival outcomes were improved compared to historic rates observed with cardiogenic shock, particularly PCCS. Prospective studies assessing comparative performance of this device to conventional strategies are warranted in future.

Ninety-Day Readmissions of Bundled Valve Patients: Implications for Healthcare Policy.

Medicare's Bundle Payment for Care Improvement (BPCI) Model 2 groups reimbursement for valve surgery into 90-day episodes of care, which include operative costs, inpatient stay, physician fees, postacute care, and readmissions up to 90 days postprocedure. We analyzed our BPCI patients' 90-day outcomes to understand the late financial risks and implications of the bundle payment system for valve patients. All BPCI valve patients from October 2013 (start of risk-sharing phase) to December 2015 were included. Readmissions were categorized as early (≤30 days) or late (31-90 days). Data were collected from institutional databases as well as Medicare claims. Analysis included 376 BPCI valve patients: 202 open and 174 transcatheter aortic valves (TAVR). TAVR patients were older (83.6 vs 73.8 years; P = 0.001) and had higher Society of Thoracic Surgery predicted risk (7.1% vs 2.8%; P = 0.001). Overall, 18.6% of patients (70/376) had one-or-more 90-day readmission, and total claim was on average 51% greater for these patients. Overall readmissions were more common among TAVR patients (22.4% (39/174) vs 15.3% (31/202), P = 0.052) as was late readmission. TAVR patients had significantly higher late readmission claims, and early readmission was predictive of late readmission for TAVR patients only (P = 0.04). Bundled claims for a 90-day episode of care are significantly increased in patients with readmissions. TAVR patients represent a high-risk group for late readmission, possibly a reflection of their chronic disease processes. Being able to identify patients at highest risk for 90-day readmission and the associated claims will be valuable as we enter into risk-bearing episodes of care agreements with Medicare.

A Contemporary Approach to Reoperative Aortic Valve Surgery: When is Less, More?

OBJECTIVE: Although the benefits of minimally invasive valvular surgery are well established, the applicability of extending these techniques to reoperative aortic valve surgery is unknown. We evaluated our experience with a minimally invasive approach to this patient population. METHODS: From January 2010 to September 2015, 21 patients underwent reoperative isolated aortic valve replacement via a minimally invasive approach by a single surgeon. All patients had preoperative evaluation with computerized tomography and coronary catheterization. Surgical approaches were right anterior thoracotomy (6/21) or upper hemisternotomy (15/21). Central aortic cannulation was preferred with femoral artery cannulation used in four patients (19%). In patients with left internal mammary artery (LIMA) grafts, no attempt to dissect or occlude the graft was made. Cold blood cardioplegia was administered antegrade (12/21) or retrograde (9/21); systemic cooling with a mean low temperature of 27.5 °C was employed. RESULTS: Mean age was 75.1 years with a range from 33 to 92 years, and 67% (14/21) were male. All procedures were completed with a minimally invasive approach. Mean ± SD cross-clamp time was 51.5 ± 9.2 minutes. Fourteen patients had patent LIMA grafts. No aortic, LIMA, or cardiac injuries occurred. There were no hospital deaths nor occurrences of perioperative myocardial infarction, stroke, wound infection, renal failure, or endocarditis/sepsis. One patient required a reoperation for bleeding. Sixty-two percent of patients were discharged to home; mean ± SD length of stay was 6 ± 3 days. CONCLUSIONS: With appropriate preoperative evaluation and careful surgical planning, a minimally invasive approach to reoperative aortic valve surgery can be performed in a safe and effective manner.

Reengineering valve patients' postdischarge management for adapting to bundled payment models.

BACKGROUND: Bundled Payments for Care Improvement (BPCI) initiatives were developed by Medicare in an effort to reduce expenditures while preserving quality of care. Payment model 2 reimburses based on a target price for 90-day episode of care postprocedure. The challenge for valve patients is the historically high (>35%) 90-day readmission rate. We analyzed our institutional cardiac surgical service line adaptation to this initiative. METHODS: On May 1, 2015, we instituted a readmission reduction initiative (RRI) that included presurgical risk stratification, comprehensive predischarge planning, and standardized postdischarge management led by cardiac nurse practitioners (CNPs) who attempt to guide any postdischarge encounters (PDEs). A prospective database also was developed, accruing data on all cardiac surgery patients discharged after RRI initiation. We analyzed detailed PDEs for all valve patients with complete 30-day follow-up through November 2015. RESULTS: Patients included 219 surgical patients and 126 transcatheter patients. Sixty-four patients had 79 PDEs. Of these 79 PDEs, 46 (58.2%) were guided by CNPs. PDEs were due to fluid overload/effusion (21, 27%), arrhythmia (17, 22%), bleeding/thromboembolic events (13, 16%), and falls/somatic complaints (12, 15%). Thirty-day readmission rate was 10.1% (35/345). Patients with transcatheter aortic valve replacement had a higher rate of readmission than surgical patients (15.0% vs 6.9%), but were older with more comorbidities. The median readmission length of stay was 2.0 days (interquartile range 1.0-5.0 days). Compared with 2014, the 30-day readmission rate for BPCI decreased from 18% (44/248) to 11% (20/175), P = .05. CONCLUSIONS: Our reengineering of pre/postdischarge management of BPCI valve patients under tight CNP control has significantly reduced costly 30-day readmissions in this high-risk population.

Long-term results of mitral valve repair with semi-rigid posterior band annuloplasty.

BACKGROUND AND AIM OF THE STUDY: Optimal repair of the mitral valve involves the implantation of an annuloplasty device to geometrically reshape and/or stabilize the annulus and improve long-term durability. It has been reported previously that trigone-to-trigone semi-rigid posterior band (PB) annuloplasty is associated with excellent short-term outcomes, physiologic motion of the anterior mitral annulus and leaflet, and lower postoperative transvalvular gradients compared to complete ring (CR) annuloplasty. The aim of this retrospective study was to compare the long-term effectiveness of PB and CR annuloplasty in patients with degenerative mitral valve regurgitation (MR). METHODS: Between 1993 and 2010, a total of 1,612 patients with degenerative MR underwent mitral valve repair (MVr) with either PB (n = 1,101) or CR (n = 511). Initially, CR was the annuloplasty device of choice, but after 2001 PB was preferred. A retrospective review of clinical and echocardiographic follow up was performed on these patients. The eight-year cumulative freedom from adverse events were determined by life-table analysis. RESULTS: Hospital mortality was 1.9% overall (n = 30/1612), but 1.3% (12/939) for isolated MVr, and 2.7% (18/673) for MVr with concomitant procedures (p = 0.04). Hospital mortality was similar for both PB (1.9%; 21/1101) and CR (1.8%; 9/511) (p = 0.8). The mean MR grade was reduced from 3.9 +/- 0.3 preoperatively to 0.6 +/- 0.9 at follow up using PB (p < 0.01), and from 3.9 +/- 0.4 to 0.9 +/- 0.9 using CR (p < 0.01). PB was associated with a similar long-term freedom from death (77 +/- 0.03% versus 83 +/- 0.02%; p = 0.4), reoperation (95 +/- 0.01% versus 92 +/- 0.01%; p = 0.06), and reoperation or recurrent severe MR (91 +/- 0.02% versus 92 +/- 0.01%; p = 0.7), and slightly greater freedom from valve-related complications compared to CR (91 +/- 0.02% versus 87 +/- 0.02%; p = 0.02). CONCLUSION: The long-term outcome of mitral valve annuloplasty with PB was comparable to that with CR for degenerative disease. Anterior annuloplasty was found to be unnecessary in this patient population.

Evolution of operative techniques and perfusion strategies for minimally invasive mitral valve repair.

OBJECTIVE: Perfusion strategies and operative techniques for minimally invasive mitral valve repair have evolved over time. During the past decade, our institution's approach has progressed from a port access platform with femoral perfusion to predominantly a central aortic cannulation through a right anterior minithoracotomy incision. We analyzed this institutional experience to evaluate the impact of approach on patient outcomes. METHODS: Between 1995 and 2007, 1282 patients (mean age, 59.3 years; range, 18-99 years) underwent first-time, isolated mitral valve repair using a minimally invasive technique. Patient demographics included peripheral vascular disease (3.2%), chronic obstructive pulmonary disease (8.3%), atherosclerotic aorta (6.5%), cerebrovascular disease (4.3%), and ejection fraction less than 30% (4.3%). Retrograde perfusion was performed in 394 (30.7%) of all patients and endoaortic balloon occlusion in 373 (29.1%); the operative technique was a right anterior minithoracotomy in 1264 (98.6%) and left posterior minithoracotomy in 18 (1.4%). The etiology of mitral disease was degenerative in 73.2%, functional in 20.6%, and rheumatic in 2.4%. Data were collected prospectively using the New York State Cardiac Surgery Report System and a customized minimally invasive surgery data form. Logistic analysis was used to evaluate risk factors and outcomes; operative experience was divided into tertiles. RESULTS: Overall hospital mortality was 2.0% (25/1282). Mortality was 1.1% (10/939) for patients with degenerative etiology and 0.4% (3/693) for patients younger than 70 years of age with degenerative valve disease. Risk factors for death were advanced age (P = .007), functional etiology (P = .010; odds ratio [OR] = 3.3), chronic obstructive pulmonary disease (P = .013; OR = 3.4), peripheral vascular disease (P = .014; OR = 4.2), and atherosclerotic aorta (P = .03; OR = 2.8). Logistic risk factors for neurologic events were advanced age (P = .02), retrograde perfusion (P = .001; OR = 3.8), and emergency procedure (P = .01; OR = 66.6). Interaction modeling revealed that the only significant risk factor for neurologic event was the use of retrograde perfusion in high-risk patients with aortic disease (P = .04; OR = 8.5). Analysis of successive tertiles during this 12-year experience revealed a significant decrease in the use of retrograde arterial perfusion (89.6%, 10.4%, and 0.0%; P < .001) and endoaortic balloon occlusion (89.3%, 10.7%, and 0%; P < .001). The overall frequency of postoperative neurologic events was 2.3% (30/1282) and decreased from 4.7% in the first tertile to 1.2% in the second and third tertiles (P < .001). CONCLUSIONS: Central aortic cannulation through a right anterior minithoracotomy for mitral valve repair allows excellent outcomes in patients with a broad spectrum of comorbidities and has become our preferred approach for most patients undergoing mitral valve repair. Retrograde arterial perfusion is associated with an increased risk of stroke in patients with severe peripheral vascular disease and should be reserved for select patients without significant atherosclerosis.

Downregulation of the hemoglobin scavenger receptor in individuals with diabetes and the Hp 2-2 genotype: implications for the response to intraplaque hemorrhage and plaque vulnerability.

In individuals with diabetes mellitus (DM), the haptoglobin (Hp) genotype is a major determinant of susceptibility to myocardial infarction. We have proposed that this is because of DM and Hp genotype-dependent differences in the response to intraplaque hemorrhage. The macrophage hemoglobin scavenging receptor CD163 plays an essential role in the clearance of hemoglobin released from lysed red blood cells after intraplaque hemorrhage. We sought to test the hypothesis that expression of CD163 is DM and Hp genotype-dependent. CD163 was quantified in plaques by immunohistochemistry, on peripheral blood monocytes (PBMs) by FACS, and as soluble CD163 (sCD163) in plasma by ELISA. In DM plaques, despite an increase in macrophage infiltration, CD163 immunoreactivity was lower, resulting in a dramatic reduction in the percentage of macrophages expressing CD163 (27+/-2% versus 70+/-2%, P=0.0001). In individuals with DM as compared with individuals without DM, the percentage of PBMs expressing CD163 was reduced (3.7+/-0.6% versus 7.1+/-0.9%, P<0.002) whereas soluble plasma CD163 was increased (2.6+/-1.1 microg/mL versus 1.6+/-0.8 microg/mL, P<0.0005). Among DM individuals, the Hp 2-2 genotype was associated with a decrease in the percentage of PBMs expressing CD163 (2.3+/-0.5% versus 5.6+/-1.3%, P=0.01) and an increase in plasma soluble CD163 (3.0+/-0.2 microg/mL versus 2.3+/-0.2 microg/mL, P=0.04). Taken together, these results demonstrate an impaired hemoglobin clearance capacity in Hp 2-2 DM individuals and may provide the key insight explaining the increased incidence of myocardial infarction in this population.

Role of prostaglandins in mediating differences in human internal mammary and radial artery relaxation elicited by hypoxia.

The effects of hypoxia-reoxygenation on internal mammary (IMA) and radial (RA) arteries used for coronary artery bypass grafting (CABG) were examined to identify mechanisms regulating contractile function and differences that could contribute to vasospasm. Isolated endothelium-intact IMA and RA rings precontracted with KCl (30 mM) rapidly dilated to hypoxia (95% N(2)/5% CO(2)) with a greater relaxation in RA than IMA. Inhibitors of cyclooxygenase (10 microM indomethacin) and the thromboxane A(2) (TxA)(2) receptor [1 microM [1S-[1alpha,2alpha(Z),3alpha,4alpha]]-7-[3-[2-(phenylamino)carbonyl]hydrazine]methyl]-7-oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid (SQ-29548)] potentiated the relaxation to hypoxia in IMA, but not RA, a response associated with increases in TxA(2). Relaxation of IMA and RA to hypoxia appears to involve a calcium-reuptake mechanism inhibited by cyclopiazonic acid (0.2 mM), and it was not attenuated by a blocker of potassium channels (10 mM TEA). The recovery of force generation of IMA, but not RA, upon reoxygenation after 30 min of hypoxia was significantly reduced in the initial phase of reoxygenation by indomethacin and SQ-29548 and by endothelin receptor blocker BQ-123 [cyclo(l-Leu-d-Trp-d-Asp-l-Pro-d-Val)]. Thus, hypoxia relaxes IMA and RA by a prostaglandin-independent mechanism potentially involving enhanced intracellular calcium reuptake. The prostaglandin-mediated alterations of responses to hypoxia-reoxygenation seen in IMA, but not in RA, may predispose IMA to vasospasm-related complications of CABG.

Open pulmonary embolectomy for treatment of major pulmonary embolism.

BACKGROUND: Inadequate data exist regarding the management of acute major pulmonary embolism. Various modalities that are used, including thrombolytics and embolectomy, have not been shown to conclusively improve mortality when compared to heparin. In the past, open pulmonary embolectomy was reserved for patients with severe hemodynamic instability because of its high mortality rate. Our objective was to analyze our experience with early embolectomy as an alternative for the treatment of major pulmonary embolism. METHODS: A retrospective review of charts of all patients undergoing pulmonary embolectomy at our institution over the last two years was performed. Patients were followed until their discharge from hospital. RESULTS: There were 13 patients (7 women and 6 men). Four had massive and 9 had submassive pulmonary embolism. There was one mortality. Postoperative echocardiography showed no evidence of pulmonary hypertension in 7. CONCLUSIONS: Open pulmonary embolectomy can be performed in patients with major pulmonary embolism with minimal mortality and morbidity. It may prevent the development of chronic thromboembolic pulmonary hypertension and should be a part of the algorithm in the treatment of major pulmonary embolism.

The effect of pulmonary circulation hemodynamics on right ventricular unloading via the bidirectional Glenn shunt: implications for congenitally corrected transposition repair.

The bidirectional Glenn shunt has been successfully applied as an adjunct to ventricular septal defect closure and pulmonary valvulotomy to treat congenitally corrected transposition of the great arteries (ccTGA). The purpose of this study was to examine the volume and pressure unloading effects of the bidirectional Glenn shunt on the hypertrophied pulmonary ventricle in a canine model of ccTGA. Five beagles underwent survival surgery to band the pulmonary artery. Three months later, a polytetrafluoroethylene graft was anastomosed to the superior vena cava and right pulmonary artery. The graft or superior vena cava was clamped to create the normal or bidirectional Glenn circulation, and hemodynamic data were recorded. The bidirectional Glenn shunt significantly reduced right ventricular volume loading and stroke work. Dogs with normal pre-bidirectional Glenn cardiac outputs had greatly reduced right ventricular volumes and pressures with the bidirectional Glenn shunt. Dogs with pre-bidirectional Glenn right ventricular dysfunction had moderate volume but no pressure decreases with the bidirectional Glenn shunt owing to improved left ventricular output. In these dogs it is likely that the decreased level of pressure and volume unloading is because of a concomitant improvement in left ventricular output post-bidirectional Glenn shunt placement. The bidirectional Glenn shunt is effective at unloading the right ventricle in a canine model of ccTGA.