Surgical Outcomes in Indigenous Peoples Undergoing Cardiac Surgery.

INTRODUCTION: Heart disease is the leading cause of death in indigenous peoples, however cardiac surgical outcomes in this group are rarely studied. We hypothesized that complication rates in indigenous peoples undergoing cardiac surgery would be similar to Caucasians. METHODS: From 2014 to 2020, 1,594 patients underwent cardiac surgery; 36 patients were identified as indigenous peoples. Risk factors, intraoperative, and postoperative variables were abstracted from our institution's database. We used the variables of age, BMI, diabetes, and tobacco use to propensity match the indigenous peoples to a group of Caucasian patients, 1:2, resulting in a total of 107 patients. Logistic regression analysis determined differences in complication rates. RESULTS: Within the propensity-matched group, indigenous peoples were more likely to be in renal failure requiring dialysis (16.7 vs. 2.9 percent, p=0.02). Indigenous peoples had a 30-day mortality of 0 percent while Caucasians had a rate of 4.3 percent (p=0.55). Postoperative complication rates were lower in indigenous peoples (22.2 percent) compared to Caucasians (35.3 percent, p=0.17). Logistic multivariate regression analysis of complication rate did not yield race as a contributing variable (odds ratio 2.05; p=0.21). CONCLUSIONS: Following cardiac surgery, indigenous peoples had a mortality rate of 0 percent and a complication rate of 22 percent. Indigenous peoples had a clinically significant lower complication rate than Caucasians, and race did not play a statistically significant role in complication rates.

Left ventricular ejection hemodynamics before and after relief of outflow tract obstruction in patients with hypertrophic obstructive cardiomyopathy and valvular aortic stenosis.

OBJECTIVE: There has been debate on the importance and pathophysiologic effects of the dynamic subaortic pressure gradient in hypertrophic obstructive cardiomyopathy. The study was conducted to elucidate the hemodynamic abnormalities associated with the dynamic pressure gradient in hypertrophic obstructive cardiomyopathy. METHODS: Eight patients with hypertrophic obstructive cardiomyopathy and 7 patients with valvular aortic stenosis underwent a detailed hemodynamic study of pressure flow relationships before and after myectomy or aortic valve replacement during operation. RESULTS: In aortic stenosis, the increased gradient after premature ventricular contraction was associated with an increase in peak flow (325 ± 122 mL/s to 428 ± 147 mL/s, P = .002) and stroke volume (75.0 ± 27.3 mL to 88.0 ± 24.0 mL, P = .004), but in hypertrophic obstructive cardiomyopathy peak flow remained unchanged (289 ± 79 mL/s to 299 ± 85 mL/s, P = .334) and stroke volume decreased (45.9 ± 18.7 mL to 38.4 ± 14.4 mL, P = .04) on the postpremature ventricular contraction beat. After myectomy, the capacity to augment stroke volume on the postpremature ventricular contraction beats was restored in patients with hypertrophic obstructive cardiomyopathy (45.6 ± 14.4 mL to 54.4 ± 11.8 mL, P = .002). CONCLUSIONS: The pressure flow relationship in hypertrophic obstructive cardiomyopathy supports the concept of true obstruction to outflow, with a low but continued flow during late systole, when the ventricular-aortic pressure gradient is the highest. Septal myectomy can abolish obstruction and restore the ability to augment stroke volume, which may explain the mechanism of symptomatic improvement after operation.

Regional and Temporal Trends in the Outcomes of Repairs for Acute Type A Aortic Dissections.

BACKGROUND: Little information exists regarding the use of arch operations for repair of acute type A aortic dissections (AADs) despite increasing interest in this strategy and its potential impact on outcomes. We aimed to determine the relationship between extent of aortic repair, US geographic regions, and outcome. METHODS: We queried The Society of Thoracic Surgeons database for patients who underwent AAD repair from January 1, 2004 to December 31, 2016 and grouped patients by ascending-only operations and operations involving the arch. RESULTS: We identified 25,462 patients (mean age, 59.8 ± 14.2; 66.7% men) who underwent AAD repair. Operations involving the ascending aorta only were performed in 54% of patients; 46% had repair additionally involving the arch. The 30-day mortality was 18.9% for patients who underwent ascending-only operations vs 19.8% for patients who underwent arch operations (P = .09). In multivariable analysis older age (P < .001), earlier year of operation (P < .001), diabetes mellitus (P < .001), severe chronic lung disease (P < .001), prior cerebrovascular disease (P < .001), and longer bypass time (P < .001) were independently associated with 30-day mortality. There was regional variation in 30-day mortality (P < .001), and incidence of arch repair varied from 38.6% to 52.6% in 9 geographic regions (P < .001). CONCLUSIONS: In this analysis of cardiac surgical practice in the United States, repair of AADs included a portion of the aortic arch in 46% of patients. Early mortality remained high throughout the current era regardless of extent of aortic resection. Regional variation in perioperative mortality may signal an opportunity for practice improvement.

Patient Experience After Cardiac Surgery: Identifying Areas for Improvement.

BACKGROUND: The Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) is a publicly reported survey of patient experience with in-hospital care. We reviewed institutional HCAHPS survey data to assess our patients' experiences after cardiac surgery and to identify targets for practice improvement. METHODS: We reviewed data from patients undergoing the most common cardiac operations, with dismissal from October 1, 2012 to September 30, 2015. We used top-box methodology to combine survey results into nine domains, including the global (composite) hospital rating, dichotomized as high versus low. Multivariable logistic regression analysis was used to evaluate the independent associations of variables with low global ratings. Key driver analysis using domain means and Spearman correlation between the global rating and the eight other domains identified targets for quality improvement. RESULTS: Among 1,315 surveyed patients a low global hospital rating was independently associated with low perceived overall health (fair or poor vs excellent; odds ratio [OR], 5.4; p = 0.001), younger age (18 to 59 vs ≥70 years; OR, 1.6; p = 0.048), prolonged length of stay (OR, 1.6; p = 0.02), and robotic mitral valve (MV) repair (robotic vs open repair; OR, 2.4; p = 0.045). Patients undergoing transcatheter aortic valve replacement (TAVR) reported global ratings similar to that of patients with open aortic valve operations (OR, 0.9; p = 0.64). Key drivers of patient experience were care transitions and communication regarding medications. CONCLUSIONS: The primary targets of improvement for our institution are care transitions and communications regarding medications. The less-invasive procedures (robotic MV repair, TAVR) were not independently associated with higher patient-experience scores.

Impact of Medical Therapy on Late Morbidity and Mortality After Aortic Aneurysm Repair for Aortitis.

BACKGROUND: Patients with active aortitis who undergo repair of ascending aortic aneurysms have an increased risk of late reoperation and decreased late survival. We aimed to determine the reasons for these poor outcomes and the influence of medical management. METHODS: We reviewed records of 186 patients (median age 73.9 years; 120 women) with noninfectious aortitis after elective ascending aortic aneurysm repair (January 1955 through December 2012). Landmark analysis was used to compare outcomes in patients with isolated aortitis versus with systemic sequelae of aortitis along with outcomes of treatment with glucocorticoids. RESULTS: At 15 years, the overall mortality was 88.3%; at 10 years, the overall reoperation rate was 28.2%. Long-term mortality increased with older age at surgery (hazard ratio [HR] 1.62, 95% confidence interval [CI]: 1.25 to 2.11, p < 0.001), coronary artery disease (HR 1.94, 95% CI: 1.25 to 3.01, p = 0.003), peripheral vascular disease (HR 1.79, 95% CI: 1.09 to 2.94, p = 0.02), and preoperative suspicion of aortitis (HR 4.90, 95% CI: 1.96 to 12.26, p < 0.001). Increased reoperation rate was associated with coronary artery disease (HR 2.69, 95% CI: 1.17 to 6.17, p = 0.02) and peripheral vascular disease (HR 3.92, 95% CI: 1.71 to 8.94, p = 0.001). Among patients free of reoperation at 6 months, systemic sequelae of aortitis were found to be significant, with an unadjusted hazard ratio of 3.59 (95% CI: 1.40 to 9.18, p = 0.008). Treatment with glucocorticoids was not associated with subsequent mortality or reoperation. CONCLUSIONS: The development of systemic illness secondary to aortitis was associated with increased risk of late aortic reoperations. However, glucocorticoid treatment of noninfectious aortitis did not clearly influence survival or need for reoperation.

Aortic Root Dilation: Do Patients With Marfan Syndrome Fare Worse Than Those With Marfanoid Features?

OBJECTIVE: To discover whether patients with aortic root dilation and leptosomic features but without a diagnosis of Marfan syndrome (MFS) fare similarly to patients with MFS. METHODS: Of 124 patients with aortic root dilation identified from August 1, 1994, through October 31, 2012, 66 had MFS and 58 had leptosomic features but did not meet the Ghent criteria. Genetic testing was performed in 35% of patients (n=43). We compared z scores and aortic root diameters for patients who presented with aortic root dilation with and without an MFS diagnosis and with and without aortic root repair. RESULTS: No difference existed in initial aortic root diameters between groups (P=.15); however, mean ± SD z scores for patients without MFS and with MFS were 3.1±2.3 vs 4.5±3.2 (P=.005). Fourteen of 58 patients (24%) without MFS and 35 (53%) with MFS underwent aortic root operations (P<.05). For both groups who did not have surgery, aortic root diameters and z scores remained similar at follow-up (P=.20), as did 10-year survival: MFS, 100%; no MFS, 94.1% (P=.98). No significant difference was found for mean ± SD root diameter (no MFS, 38.9±7.3 mm; MFS, 35±8.6 mm; P=.06) or z score (no MFS, 2.4±2.0; MFS, 2.1±2.0; P=.53) for patients who underwent surgery. Two patients in each group had aortic root dissections. CONCLUSION: Similar rates of aortic dissection between the 2 groups warrant further study regarding patients with leptosomic features but no diagnosis of MFS. Aortic root dilation progressed similarly in patients who did not undergo surgery.

Xenoantigenicity of porcine decellularized valves.

BACKGROUND: The xenoantigenicity of porcine bioprosthetic valves is implicated as an etiology leading to calcification and subsequent valve failure. Decellularization of porcine valves theoretically could erase the antigenicity of the tissue leading to more durable prosthetic valves, but the effectiveness of decellularization protocols in regard to completely removing antigens has yet to be verified. Our hypothesis was that decellularization would remove the more abundant α-gal antigens but not remove all the non α-gal antigens, which could mount a response. METHODS: Porcine aortic valves were decellularized with 1% sodium dodecyl sulfate for 4 days. Decellularized cusps were evaluated for α-gal epitopes by ELISA. To test for non α-gal antigens, valves were implanted into sheep. Serum was obtained from the sheep preoperatively and 1 week, 1 month, and 2 months postoperatively. This serum was utilized for anti-porcine antibody staining and for quantification of anti-pig IgM and IgG antibodies and complement. RESULTS: Decellularized porcine cusps had 2.8 ± 2.0% relative α-gal epitope as compared to fresh porcine aortic valve cusps and was not statistically significantly different (p = 0.4) from the human aortic valve cusp which had a 2.0 ± 0.4% relative concentration. Anti-pig IgM and IgG increased postoperatively from baseline levels. Preoperatively anti-pig IgM was 27.7 ± 1.7 µg/mL and it increased to 71.9 ± 12.1 µg/mL average of all time points postoperatively (p = 0.04). Preoperatively anti-pig IgG in sheep serum was 44.9 ± 1.5 µg/mL and it increased to 72.6 ± 6.0 µg/mL average of all time points postoperatively (p = 0.01). There was a statistically significant difference (p = 0.00007) in the serum C1q concentration before valve implantation (2.5 ± 0.2 IU/mL) and at averaged time points after valve implantation (5.3 ± 0.3 IU/mL). CONCLUSIONS: Decellularization with 1% sodium dodecyl sulfate does not fully eliminate non α-gal antigens; however, significant reduction in α-gal presence on decellularized cusps was observed. Clinical implications of the non α-gal antigenic response are yet to be determined. As such, evaluation of any novel decellularized xenografts must include rigorous antigen testing prior to human trials.

Low-Dose Gamma Irradiation of Decellularized Heart Valves Results in Tissue Injury In Vitro and In Vivo.

BACKGROUND: Decellularized heart valves are emerging as a potential alternative to current bioprostheses for valve replacement. Whereas techniques of decellularization have been thoroughly examined, terminal sterilization techniques have not received the same scrutiny. METHODS: This study evaluated low-dose gamma irradiation as a sterilization method for decellularized heart valves. Incubation of valves and transmission electron microscopy evaluation after different doses of gamma irradiation were used to determine the optimal dose of gamma irradiation. Quantitative evaluation of mechanical properties was done by tensile mechanical testing of isolated cusps. Sterilized decellularized heart valves were tested in a sheep model (n = 3 [1 at 1,500 Gy and 2 at 3,000 Gy]) of pulmonary valve replacement. RESULTS: Valves sterilized with gamma radiation between 1,000 Gy and 3,000 Gy were found to be optimal with in vitro testing. However, in vivo testing showed deteriorating valve function within 2 months. On explant, the valve with 1,500 Gy gamma irradiation showed signs of endocarditis with neutrophils on hematoxylin and eosin staining, and positive gram stain resembling streptococcus infection. The 3,000 Gy valves had no evidence of infection, but the hematoxylin and eosin staining showed evidence of wound remodeling with macrophages and fibroblasts. Tensile strength testing showed decreased strength (0 Gy: 2.53 ± 0.98 MPa, 1,500 Gy: 2.03 ± 1.23 MPa, and 3,000 Gy: 1.26 ± 0.90 MPa) with increasing levels of irradiation. CONCLUSIONS: Low-dose gamma irradiation does not maintain the mechanical integrity of valves, and the balance between sterilization and damage may not be able to be achieved with gamma irradiation. Other methods of terminal sterilization must be pursued and evaluated.

Basic Cardiac Surgery Skills on Sale for $22.50: An Aortic Anastomosis Simulation Curriculum.

BACKGROUND: Current resident and student duty-hour restrictions necessitate efficient training, which may be aided by simulation. Data on the utility of low-cost simulation in cardiothoracic surgery are scant. We evaluated the effect and value of a low-cost, low-fidelity aortic anastomosis simulation curriculum. METHODS: Twenty participants (11 medical students, 9 residents) completed an aortic anastomosis on a porcine heart as a pretest. Participants were then provided access to a 14-minute online video created by a cardiac surgeon and given a low-cost task trainer for self-directed practice. Five weeks later, participants performed another aortic anastomosis on a porcine heart as a posttest. Pretest and posttest performances were filmed, deidentified, and graded blindly and independently by two cardiac surgeons using a standardized assessment tool (perfect score, 110; passing score, 58 or higher). Participants were surveyed anonymously after the posttest. RESULTS: The mean (SD) aortic anastomosis performance score improved significantly from pretest (53.3 [25.3]) to posttest (83.6 [15.3]; p < 0.001). Pass rates also improved significantly (35% versus 95%, p < 0.001). Medical students' scores improved most (p = 0.01). All 20 participants reported improved confidence in performing the task, and 18 believed that the online video was essential to better performance. The cost of the curriculum totaled $22.50 per participant, with 6 hours of total staff time required for assessment. CONCLUSIONS: An aortic anastomosis training and simulation curriculum improves the skills of student and resident trainees with minimal expense and staff time commitment. Such a curriculum may be of great value to both cardiothoracic training programs and their trainees.

Influence of aortitis on late outcomes after repair of ascending aortic aneurysms.

OBJECTIVE: To determine outcomes of repair of ascending aortic aneurysms in patients with histopathologic diagnoses of aortitis. METHODS: We reviewed histopathologic findings and outcomes of elective repair of ascending aortic aneurysms between January 1, 1955, and December 31, 2012. Noninfectious aortitis was identified in 186 patients, and we compared outcomes for these patients with outcomes for others operated on at the same time with diagnoses of medial degeneration (n = 317) or atherosclerosis (n = 232). RESULTS: Early mortality (<30 days postoperatively) for patients with aortitis was 2%, and overall 10-year survival was 45%, compared with 66% for patients with medial degeneration, and 45% for patients with atherosclerosis (P < .001 vs medial degeneration). In addition to histopathologic diagnosis, overall mortality was influenced by older age at operation (hazard ratio [HR]: 1.060; 95% confidence interval [CI], 1.046-1.077; P < .001), chronic obstructive pulmonary disease (HR: 1.560; 95% CI: 1.136-2.136; P = .006); concomitant coronary artery bypass grafting (HR: 1.980; 95% CI: 1.520-2.600; P < .001); and use of circulatory arrest (HR: 1.500; 95% CI: 1.148-1.960; P = .003). Risk of aortic reoperation at 10 years was 21% for aortitis patients, compared with 11% for those with medial degeneration, and 19% for patients with atherosclerosis (P = .028). CONCLUSIONS: Patients with repaired ascending aneurysms secondary to noninfectious aortitis have low early mortality, but late risks of death and aortic reoperation are increased, compared with these outcomes for patients with aneurysms that result from medial degeneration.