Long-term Outcomes After Reoperative Coronary Artery Bypass Grafting.

BACKGROUND: Reoperative coronary artery bypass grafting (CABG) surgery has an established increased operative risk with worse perioperative morbidity and mortality. However, contemporary propensity-matched outcomes are limited in the existing literature. METHODS: All patients who underwent CABG from 2011 to 2017 at the University of Pittsburgh Medical Center in Pittsburgh, Pennsylvania were included. Propensity matching yielded risk-adjusted patient populations. Cox regression analysis was performed to identify independent predictors of 30-day, 1-year, and 5-year mortality and readmission. RESULTS: The total population consisted of 7615 patients who underwent CABG; 7265 of these patients had first-time CABG, and 350 patients had reoperative CABG. After propensity score matching, blood product transfusion (45.5% vs 56.4%; P = .002) and delayed sternal closure (0.2% vs 2.5%; P < .001) remained significantly higher for reoperative CABG. There was no difference in 30-day (5.3% vs 7.5%; P = .19) or 1-year (12.1% vs 14.8%; P = .23) mortality for first-time vs reoperative CABG. Five-year mortality was significantly higher for the reoperative cohort (28.5% vs 38.3%; P = .03). There was no difference in 30-day, 1-year, or 5-year hospital readmissions. On Cox multivariable regression analysis, reoperative CABG was not a predictor of mortality or readmission at 30 days, 1 year, or 5 years. CONCLUSIONS: After propensity score matching, there was no difference in postoperative mortality or readmission for reoperative CABG up to 1-year. This trend continued for 5-year readmissions; however, 5-year mortality was higher for the reoperative cohort. Risk adjustment did not identify reoperative CABG as a risk factor for long-term mortality.

Percutaneous coronary intervention versus coronary artery bypass grafting in patients with reduced ejection fraction.

OBJECTIVE: The aim of this study was to evaluate comparative outcomes for percutaneous coronary intervention (PCI) versus coronary artery bypass grafting (CABG) in patients with reduced ejection fraction. METHODS: All patients from the University of Pittsburgh Medical Center from 2011 to 2018 who had reduced preoperative ejection fraction (<50%) and underwent CABG or PCI for coronary revascularization were included in this study. Patients were risk-adjusted with propensity matching (1:1) and primary outcomes included long-term survival, readmission, and major adverse cardiac and cerebrovascular events (MACCE). RESULTS: A total of 2000 patients were included in the current study, consisting of CABG (n = 1553) and PCI (n = 447) cohorts with a mean ejection fraction of 35% ± 9.53%. Propensity matching yielded a 1:1 match with 324 patients in each cohort, controlling for all baseline characteristics. Thirty-day mortality was similar for PCI versus CABG (6.2% vs 4.9%; P = .49). Overall mortality over the study follow-up period (median, 3.23 years; range, 1.83-4.98 years) was significantly higher for the PCI cohort (37.4% vs 21.3%; P < .001). Total hospital readmissions (24.1% vs 12.9%; P = .001), cardiac readmissions (20.4% vs 11.1%; P = .001), myocardial infarction event (7.7% vs 1.8%; P = .001), MACCE (41.4% vs 23.8%; P < .001), and repeat revascularization (6.5% vs 2.6%; P = .02) occurred more frequently in the PCI cohort. Freedom from MACCE at 1 year (74.4% vs 87.0%; P < .001) and 5 years (54.5% vs 74.0%; P < .001) was significantly lower for the PCI cohort. On multivariable cox regression analysis, CABG (hazard ratio, 0.57; 95% confidence interval, 0.44-0.73; P < .001) was significantly associated with improved survival. Prior liver disease, dialysis, diabetes, and peripheral artery disease were the most significant predictors of mortality. The cumulative incidence of hospital readmission was lower for the CABG cohort (hazard ratio, 0.51; 95% confidence interval, 0.37-0.71; P < .001). Multivariable cox regression for MACCE (hazard ratio, 0.48; 95% confidence interval, 0.39-0.58; P < .001) showed significantly fewer events for the CABG cohort. CONCLUSIONS: Patients with reduced ejection fraction who underwent CABG had significantly improved survival, lower MACCE, and fewer repeat revascularization procedures compared with patients who underwent PCI.

Long-term Impact of Perioperative Red Blood Cell Transfusion on Patients Undergoing Cardiac Surgery.

BACKGROUND: There is a known association between need for transfusion and short-term outcomes in patients undergoing cardiac surgery. However long-term data are lacking in the contemporary literature. METHODS: All patients who underwent open cardiac surgery from 2010 to 2018 were included, except those undergoing transplant, with a ventricular-assist device, and requiring circulatory arrest. Primary outcome included short- and long-term mortality. Secondary outcomes included postoperative complications and hospital readmissions. RESULTS: The total patient population included 14,281 patients with a median follow-up of 4.03 years (range, 2.25-6.1). Outcomes were stratified into patients with (n = 6239) or without (n = 8042) packed red blood cell (PRBC) use. Patients with PRBC transfusions had significantly (P < .001) worse postoperative outcomes compared with those without PRBC use, including higher operative mortality (6.89% vs 0.98%), return to the operating room (17.8% vs 1.61%), pneumonia (7.84% vs 0.98%), stroke (3.22% vs 1.51%), sepsis (2.66% vs 0.20%), renal failure (8.42% vs 1.12%), and dialysis (5.74% vs 0.42%). On multivariate analysis PRBC transfusion was an independent predictor of mortality (hazard ratio [[HR], 2.39; 95% confidence interval [CI], 2.08-2.64; P < .001) and hospital readmission (HR, 1.15; 95% CI, 1.09-1.21; P < .001). Total units of PRBCs were directly associated with mortality (HR, 1.09; 95% CI, 1.08-1.09; P < .001) and hospital readmissions (HR, 1.02; 95% CI, 1.01-1.03; P < .005). CONCLUSIONS: Patients with perioperative PRBC transfusions have increased operative and long-term mortality and hospital readmissions. Total units of PRBCs transfused were directly associated with mortality and readmissions.

Midterm outcomes of subcoronary stentless porcine valve versus stented aortic valve replacement.

INTRODUCTION: Stentless porcine xenografts are versatile bioprosthetic valves with the advantage of improved hemodynamics that mimic the function of the native aortic valve. However, these bioprostheses are challenging to implant in the subcoronary position. METHODS: All consecutive patients who underwent a bioprosthetic aortic valve replacement (AVR) were included from our institutional database. Cox regression analysis was preformed to determine significant predictors for mid term mortality as well as all cause, cardiac, and heart failure readmission. RESULTS: Patients in the subcoronary stentless group were older and more likely to be female and were likely to have a higher Society of Thoracic Surgery risk of mortality. Survival was superior in the stented AVR cohort at 30-days (96.4% vs 90.5%; P < .001), 1-year (90.5% vs 71.6%; P < .001), and 5-year (74.5% vs 56.9%; P < .001) follow up. Acute kidney injury (16.22% vs 5.22%; P < .001) and blood product transfusion (70.27% vs 44.0%; P < .001) were higher in the stentless group. Multivariable analysis revealed subcoronary stentless implantation as a significant independent risk factor for mortality (hazards ratio: 1.92 [1.35,2.72]; P < .001). CONCLUSION: Stentless porcine xenograft implantation with the Freestyle bioprosthetic in the subcoronary position can be successfully performed in select patients, but its use is associated with increased perioperative morbidity and mortality affecting midterm outcomes. Individual patient selection and surgeon experience are important to ensure favorable outcomes.

Outcomes of left renal vein stenting in patients with nutcracker syndrome.

BACKGROUND: Nutcracker syndrome (NCS) is a rare condition that can be manifested with hematuria, flank pain, pelvic varicosities, or chronic pelvic congestion related to left renal vein (LRV) compression. Open surgery, specifically LRV transposition, has been the mainstay of treatment, but in the past few years, LRV stenting has emerged as a less invasive alternative without sufficient evidence to support it. This study aimed to assess outcomes of renal vein stenting in the treatment of NCS. METHODS: A retrospective chart review of patients with NCS who underwent LRV stenting between 2010 and 2018 was performed. End points were perioperative adverse outcomes, symptom relief, and stent patency. Symptom resolution was classified as complete, partial, and none on the basis of the interpretation of medical records on clinical follow-up. Standard descriptive statistics and survival analysis were used. RESULTS: Eighteen patients (17 female; mean age, 38.1 ± 16.9 years) diagnosed with NCS and treated with LRV stenting were identified. Five of these had a prior LRV transposition that had failed within a mean of 7.0 ± 4.9 months, manifested by symptom recurrence (or no improvement) along with imaging evidence of persistently severe renal vein stenosis. Twelve patients had coexisting pelvic congestion syndrome treated with gonadal vein embolization. The most frequent sign and symptom were hematuria (10/18 patients) and flank pain (15/18 patients), respectively. All patients received self-expanding stents (mean diameter, 12.8 ± 1.6 mm), the smaller ones typically placed in the previously transposed LRVs. No perioperative complications occurred. Nine patients were discharged on the same day; the remaining patients stayed longer for pain control (mean hospital stay, 1.0 ± 1.3 days). At an average follow-up of 41.4 ± 26.6 months, 13 (72.2%) patients had symptoms resolved or improved (9 complete, 4 partial). Three of the five patients whose symptoms remained unchanged had previous LRV transposition surgery, and two of these three patients eventually required renal autotransplantation. Six of 10 patients who presented with hematuria had it resolved. Three patients underwent a stent reintervention at 5.8 months, 16.8 months, and 51.7 months because of symptom recurrence or stent restenosis. The two early ones required balloon venoplasty and the third one restenting. Two-year primary and primary assisted patency was 85.2% and 100%, respectively. No stent migration occurred. CONCLUSIONS: Endovascular treatment with renal vein stenting is safe, providing encouraging results with good midterm patency rates and symptom relief. Minimally invasive approaches may have a potential role in the treatment of NCS. Larger series and longer follow-up are needed to better assess the comparative performance against LRV transposition.

Graft-infiltrating host dendritic cells play a key role in organ transplant rejection.

Successful engraftment of organ transplants has traditionally relied on preventing the activation of recipient (host) T cells. Once T-cell activation has occurred, however, stalling the rejection process becomes increasingly difficult, leading to graft failure. Here we demonstrate that graft-infiltrating, recipient (host) dendritic cells (DCs) play a key role in driving the rejection of transplanted organs by activated (effector) T cells. We show that donor DCs that accompany heart or kidney grafts are rapidly replaced by recipient DCs. The DCs originate from non-classical monocytes and form stable, cognate interactions with effector T cells in the graft. Eliminating recipient DCs reduces the proliferation and survival of graft-infiltrating T cells and abrogates ongoing rejection or rejection mediated by transferred effector T cells. Therefore, host DCs that infiltrate transplanted organs sustain the alloimmune response after T-cell activation has already occurred. Targeting these cells provides a means for preventing or treating rejection.

Renal dendritic cells sample blood-borne antigen and guide T-cell migration to the kidney by means of intravascular processes.

Bony fish are among the first vertebrates to possess an innate and adaptive immune system. In these species, the kidney has a dual function: filtering solutes similar to mammals and acting as a lymphoid organ responsible for hematopoiesis and antigen processing. Recent studies have shown that the mammalian kidney has an extensive network of mononuclear phagocytes, whose function is not fully understood. Here, we employed two-photon intravital microscopy of fluorescent reporter mice to demonstrate that renal dendritic cells encase the microvasculature in the cortex, extend dendrites into the peritubular capillaries, and sample the blood for antigen. We utilized a mouse model of systemic bacterial infection as well as immune complexes to demonstrate antigen uptake by renal dendritic cells. As a consequence, renal dendritic cells mediated T-cell migration into the kidney in an antigen-dependent manner in the setting of bacterial infection. Thus, renal dendritic cells may be uniquely positioned to play an important role not only in surveillance of systemic infection but also in local infection and autoimmunity.

Further evidence for sustained systemic inflammation in xenograft recipients (SIXR).

INTRODUCTION: In pig-to-baboon heart/artery patch transplantation models, adequate costimulation blockade prevents a T-cell response. After heart transplantation, coagulation dysfunction (thrombocytopenia, reduced fibrinogen, increased D-dimer) and inflammation (increased C-reactive protein [CRP]) develop. We evaluated whether coagulation dysfunction and/or inflammation can be detected following pig artery patch transplantation. METHODS: Baboons received heart (n = 8) or artery patch (n = 16) transplants from genetically engineered pigs and a costimulation blockade-based regimen. Heart grafts functioned for 15-130 days. Artery recipients were euthanized after 28-84 days. Platelet counts, fibrinogen, D-dimer, and CRP were measured. RESULTS: Thrombocytopenia and reduced fibrinogen developed only in recipients of hearts not expressing a coagulation-regulatory protein (n = 4), but not in other heart or patch recipients. However, in heart recipients (n = 8), there were sustained increases in D-dimer (<0.5 to 1.9 ug/ml [P < 0.01]) and CRP (0.26-2.2 mg/dl [P < 0.01]). In recipients of artery patches, there were also sustained increases in D-dimer (<0.5 to 1.4 ug/ml [P < 0.01]) and CRP (0.26 to 1.5 mg/dl [P < 0.001]). An IL-6R antagonist suppressed the increase in CRP, but not D-dimer. CONCLUSION: The pig artery patch model has proved valuable for determining immunosuppressive regimens that prevent sensitization to pig antigens. This model also provides information on the sustained systemic inflammation in xenograft recipients (SIXR). An IL-6R antagonist may help suppress this response.