Evaluation of Extracorporeal Membrane Oxygenation Therapy as a Bridging Method

BACKGROUND

With the implementation of the new heart allocation system, heart transplantation teams are prompted to reevaluate management of patients requiring mechanical circulatory support. The purpose of our study is to compare the outcomes of patients supported with extracorporeal membrane oxygenation (ECMO) before transplantation.

METHODS

The United Network for Organ Sharing database was queried for all adult patients (aged 18 years or more) who required support with ECMO before heart transplantation from 2001 to 2018. Patients were stratified into patients who did not require ECMO before transplantation, who were weaned off ECMO before transplantation, who were bridged immediately to transplantation from ECMO, and who were bridged to a left ventricular assist device (LVAD) before transplantation. Demographics and outcomes including 1-year survival, postoperative stroke, postoperative renal failure requiring dialysis, episodes of rejection, and graft failure were compared.

RESULTS

Overall, 29,370 patients did not require ECMO before transplantation, 101 patients were weaned off ECMO before transplantation, 118 were bridged from ECMO directly to transplantation, and 55 patients were successfully bridged from ECMO to LVAD before transplantation. Kaplan-Meier survival estimates found a statistically significant decrease in 1-year survival for patients who were bridged from ECMO to transplantation compared with patients who were bridged to LVAD before subsequent transplantation (P < .001).

CONCLUSIONS

Our study suggests bridging ECMO patients to an LVAD before transplantation will result in improved 1-year survival compared with patients bridged to immediate transplantation. With the new heart allocation system, continued evaluation of outcomes is required to inform management strategies.

Sickle Cell-Related Complications in Patients Undergoing Cardiopulmonary Bypass

BACKGROUND

We aimed to describe our experience with patients with sickle cell trait (SCT) and undergoing surgery on cardiopulmonary bypass (CPB).

METHODS

Data on all patients with SCT or sickle-α thalassemia who underwent surgery on CPB were collected (1996-2017).

RESULTS

Overall, 46 patients were included, 37 (80%) had SCT and 9 (20%) had sickle-α thalassemia. A total of 4 (9%) developed a potential sickle cell-related complication. Patients with sickle cell-related complications were significantly older (median 14 years vs 14 months, P = .037) and heavier (median 54 kg vs 9 kg, P = .041). Complications occurred, although without statistical significance, in patients who underwent longer median CPB times (249 minutes vs 137 minutes, P = .069), lower median temperature (31.7 °C vs 33.3 °C, P = .094), and a higher percentage underwent deep hypothermic circulatory arrest (50% vs 7%, P = .053). A total of 30 (65%) patients underwent exchange transfusion (ET) pre-bypass. Patients who underwent ET were significantly older (median 4 years vs 7 months, P = .003) and heavier (median 16 kg vs 6 kg, P = .015) than patients who did not undergo ET. The incidence of complications was comparable between patients who underwent ET (10%) and those who did not (6%).

CONCLUSIONS

In this retrospective, single-center study, it has been shown that cardiac surgery requiring CPB in patients with SCT and sickle-α thalassemia had a low risk for sickle cell-associated complications. In this cohort of patients, older age, longer CPB times, lower median temperature, and the utilization of deep hypothermic circulatory arrest appear to play an important role in the development of complications.

Diaphragm Paralysis After Pediatric Cardiac Surgery: An STS Congenital Heart Surgery Database Study

BACKGROUND

Previous single-center studies of diaphragm paralysis (DP) after pediatric cardiac surgery report incidence of 0.3% to 12.8% and associate DP with respiratory complications, prolonged ventilation and length of stay, and mortality. To better define incidence and associations between DP and various procedures and outcomes, we performed a multicenter study.

METHODS

The Society of Thoracic Surgeons Congenital Heart Surgery Database was queried to identify children who experienced DP after cardiac surgery (2010-2018; 126 centers). Baseline characteristics and postoperative outcomes were compared between patients with and without DP as well as between patients who underwent plication and those who did not. Associations between center volume and center rates of DP and use of plication were also explored.

RESULTS

A total of 2214 of 191,463 (1.2%) patients experienced DP. Postoperative DP portended worse outcomes, including mortality (5.6% vs 3.5%; P < .001), major morbidity (37.2% vs 10.7%; P < .001), tracheostomy (7.1% vs 0.9%; P < .001), prolonged mechanical ventilation (38.0% vs 7.8%; P < .001), and 30-day readmission (22.0% vs 10.6%; P < .001). A total of 1105 of 2214 (49.9%) patients with DP underwent plication. Patients who underwent plication were younger, were smaller, had more risk factors, and underwent more complex surgeries. Plication rates varied widely across centers. There was no correlation between center volume and center risk-adjusted rates of DP (r = .05, P = .5), nor frequency of plication (r = .08, P = .4).

CONCLUSIONS

DP complicating pediatric heart surgery is rare but portends significantly worse outcomes. One-half of patients underwent plication. Center-level risk-adjusted rates of DP and plication are not associated with case volume. Significant variability in plication practices suggests a target for quality improvement.

Anomalous Aortic Origin of a Coronary Artery: Surgical Emergency?

Anomalous aortic origin of a coronary artery is a congenital condition associated with sudden cardiac death. There are no current recommendations for the acute management and urgency for this patient population. This manuscript describes and discusses two patients who presented with an acute coronary event and needed emergent intervention despite initial clinical stabilization and improvement.

Myocardial Ischemia in Children With Anomalous Aortic Origin of a Coronary Artery With Intraseptal Course

Background:

Intraseptal anomalous aortic origin of a coronary artery is considered a benign condition. However, there have been case reports of patients with myocardial ischemia, arrhythmia, and sudden cardiac death. The purpose of this study was to determine the clinical presentation, myocardial perfusion on provocative stress testing, and management of children with anomalous aortic origin of a coronary artery with an intraseptal course in a prospective cohort.

Methods:

Patients with anomalous aortic origin of a coronary artery and intraseptal course were prospectively enrolled from December 2012 to May 2019, evaluated, and managed following a standardized algorithm. Myocardial perfusion was assessed using stress imaging. Fractional flow reserve was performed in patients with myocardial hypoperfusion on noninvasive testing. Exercise restriction, β-blockers, and surgical intervention were discussed with the families.

Results:

Eighteen patients (female 6, 33.3%), who presented with no symptoms (10, 55.6%), nonexertional (4, 22.2%), and exertional symptoms (4, 22.2%), were enrolled at a median age of 12.4 years (0.3–15.9). Perfusion imaging was performed in 14/18 (77.8%) and was abnormal in 7/14 (50%); fractional flow reserve was positive in 5/8 (62.5%). All 4 patients with exertional symptoms and 3/10 (30%) with no or nonexertional symptoms had myocardial hypoperfusion. Coronary artery bypass grafting was performed in a 4-year-old patient; β-blocker and exercise restriction were recommended in 4 patients not suitable for surgery. One patient had nonexertional chest pain and 17 were symptom-free at median follow-up of 2.5 years (0.2–7.1).

Conclusions:

Up to 50% of patients with intraseptal anomalous aortic origin of a coronary artery had inducible myocardial hypoperfusion during noninvasive provocative testing. Long-term follow-up is necessary to understand the natural history of this rare anomaly.

Outcomes in Anomalous Aortic Origin of a Coronary Artery Following a Prospective Standardized Approach

Background:

Anomalous aortic origin of a coronary artery (CA) is the second leading cause of sudden cardiac death in young athletes. Management is controversial and longitudinal follow-up data are sparse. We aim to evaluate outcomes in a prospective study of anomalous aortic origin of CA patients following a standardized algorithm.

Methods:

Patients with anomalous aortic origin of a CA were followed prospectively from December 2012 to April 2017. All patients were evaluated following a standardized algorithm, and data were reviewed by a dedicated multidisciplinary team. Assessment of myocardial perfusion was performed using stress imaging. High-risk patients (high-risk anatomy—anomalous left CA from the opposite sinus, presence of intramurality, abnormal ostium—and symptoms or evidence of myocardial ischemia) were offered surgery or exercise restriction (if deemed high risk for surgical intervention). Univariate and multivariable analyses were used to determine predictors of high risk.

Results:

Of 201 patients evaluated, 163 met inclusion criteria: 116 anomalous right CA (71%), 25 anomalous left CA (15%), 17 single CA (10%), and 5 anomalous circumflex CA (3%). Patients presented as an incidental finding (n=80, 49%), with exertional (n=31, 21%) and nonexertional (n=32, 20%) symptoms and following sudden cardiac arrest/shock (n=5, 3%). Eighty-two patients (50.3%) were considered high risk. Predictors of high risk were older age at diagnosis, black race, intramural course, and exertional syncope. Most patients (82%) are allowed unrestrictive sports activities. Forty-seven patients had surgery (11 anomalous left CA and 36 anomalous right CA), 3 (6.4%) remained restricted from sports activities. All patients are alive at a median follow-up of 1.6 (interquartile range, 0.7–2.8) years.

Conclusions:

In this prospective cohort of patients with anomalous aortic origin of a CA, most have remained free of exercise restrictions. Development of a multidisciplinary team has allowed a consistent approach and may have implications in risk stratification and long-term prognosis.

Twenty-Three-Year Experience With the Arterial Switch Operation: Expectations and Long-Term Outcomes

We aimed to describe the short- and long-term outcomes of patients after an arterial switch operation (ASO) at a single institution during a 23-year period. A retrospective chart review of all patients <18 months of age who underwent an ASO between January 1995 and March 2018 at Texas Children's Hospital, Houston, TX was performed. Primary endpoints include mortality and reintervention. Perioperative mortality was defined as mortality occurring in-hospital and/or <30 days after surgery. Survival and freedom-from-reintervention were analyzed using Kaplan-Meier method, log-rank tests, and Cox regression models. The cohort included 394 patients. Diagnoses included 204 patients (52%) with intact ventricular septum, 137 (35%) with a ventricular septal defect, 17 (4%) with a ventricular septal defect and left ventricular outflow tract obstruction (LVOTO), and 36 (9%) with Taussig-Bing anomaly. Median age at surgery was 8 days (range: 1 day to 17 months) and median weight was 3.4 (range: 0.8-12.0) kg. Overall perioperative mortality was 1.3% (n = 5), 0.3% (n = 1) since 1999. Overall survival at 5, 10, and 15 years was 98.2%, 97.8%, and 97.8%, respectively. Perioperative morality was associated with prematurity (P = 0.012), <2.5 kg (P< 0.001), and longer circulatory arrest (P = 0.024) after univariate analysis. Reintervention was associated with a longer cross-clamp time (P < 0.001), <2.5 kg (P = 0.009), LVOTO resection (P = 0.047), and genetic syndrome (P= 0.011) after multivariable analysis. Current ASO expectations should include a perioperative mortality risk of <1% and good long-term survival. Reinterventions are more frequent in patients <2.5 kg, concomitant LVOTO resection, a genetic syndrome, and longer cross-clamp time.

Contemporary Outcomes following Redo Autogenous Infrainguinal Bypass

BACKGROUND

Revascularization after lower extremity bypass failure poses many challenges. Despite nearly 7 decades of experience with lower extremity revascularization, there is little data on the success of redo bypass particularly when autogenous conduit is utilized. The purpose of this study is to review outcomes of redo infrainguinal bypass constructed solely of autogenous vein.

METHODS

All patients who underwent redo infrainguinal bypass at a single institution by a single surgeon were retrospectively reviewed. Bypasses were categorized into 3 groups: femoral-popliteal, femoral-distal, and popliteal-distal bypasses. Since the repeat bypasses were all done for limb salvage, freedom from above or below knee amputation (FFA) was primary outcome, which was defined as the number of days from redo bypass to subsequent amputation or the most recent follow-up.

RESULTS

From 2006 to 2016, 100 limbs underwent redo bypass. Fifty-nine (59.0%) limbs had undergone one previous bypass while 41 (41.0%) had undergone 2 or more. The redo configurations consisted of 23 (23.0%) femoral-popliteal, 70 (70.0%) femoral-distal, and 7 (7.0%) popliteal-distal bypasses. Ninety-seven (97.0%) underwent redo using autologous vein grafts including 41 (95.5%) of those who had 2 or more previous bypasses. The 3 patients who ultimately underwent prosthetic bypass had bilateral great and small saphenous veins and bilateral basilic and cephalic veins previously harvested. Nine (9.0%) limbs were subsequently amputated: 2 (2.0%) above knee and 7 (7.0%) below knee amputations. Of these, all had had 2 or more previous bypasses and 2 of the 3 patients who ultimately received prosthetic bypasses were in this group. In patients with one previous bypass, FFA was 775 days (IQR: 213-1,626 days). In patients with 2 or more previous bypasses, FFA was 263 days (IQR: 106-1,148 days). No patients with femoral-popliteal bypasses suffered amputation while 7 (10.0%) of the femoral-distal and 2 (28.6%) of the popliteal-distal bypasses suffered subsequent amputations (P = 0.067).

CONCLUSIONS

Redo infrainguinal bypass is effective in salvaging threatened lower extremities. Furthermore, once a patient is deemed a bypass candidate, revascularization with autologous vein can be achieved. A significant FFA rate is achieved with redo bypass, although patients with more distal disease are harder to salvage.

Effects of Systemic and Device-Related Complications in Patients Bridged to Transplantation With Left Ventricular Assist Devices

BACKGROUND

The use of left ventricular assist devices (LVADs) as a bridge to heart transplantation has increased rapidly over the last 2 decades. We aim to explore the effect of pretransplant systemic and device-related complications on posttransplant survival for patients bridged with LVADs.

MATERIALS AND METHODS

The United Network of Organ Sharing (Organ Procurement and Transplantation Network) database was queried for all adult heart transplant recipients (aged ≥ 18 y) transplanted from April 1, 2015, to June 31, 2018. Device-related complications included thrombosis, device infection, device malfunction, life-threatening arrhythmia, and other device complications. Systemic complications included a new dialysis need or ventilator dependence between the time of listing and transplantation, transfusion, or systemic infection requiring treatment with intravenous antibiotics within 2 wk of transplantation.

RESULTS

A total of 2131 patients were identified as requiring LVAD support before transplantation. LVAD patients had high rates of preoperative systemic complications (53%) and high rates of device-related complications (42.7% experienced at least one device-related complication). Kaplan-Meier analysis revealed a significantly decreased 1-y survival for LVAD patients bridged to transplantation who experienced a pretransplant systemic complication (P = 0.041). Interestingly, preoperative device-related complications had no effect on 1-y posttransplantation survival (P = 0.93). Multivariate Cox modeling revealed that systemic complications were associated with a significantly increased risk of posttransplant mortality for LVAD patients (hazard ratio 1.45; P = 0.033).

CONCLUSIONS

Recipients who suffered a systemic complication while awaiting heart transplantation experienced higher short-term mortality rates. Device-related complications do not appear to impact posttransplantation outcomes.

Impact of the New Pulmonary Hypertension Definition on Heart Transplant Outcomes: Expanding the Hemodynamic Risk Profile

BACKGROUND

At the recent 6th World Symposium on Pulmonary Hypertension (PH), the definition of PH was redefined to include lower pulmonary artery pressures in the setting of elevated pulmonary vascular resistance (PVR). However, the relevance of this change to subjects with PH due to left-heart disease as well as the preoperative assessment of heart transplant (HT) recipients is unknown.

METHODS

The United Network for Organ Sharing database was queried to identify adult recipients who underwent primary HT from 1996 to 2015. Recipients were subdivided into those with mean pulmonary artery pressure (mPAP) < 25 mm Hg and ≥ 25 mm Hg. Exploratory univariable analysis was undertaken to identify candidate risk factors associated with 30-day and 1-year survival (conditional on 30-day survival) in recipients with mPAP < 25 mm Hg, and subsequently, parsimonious multivariable Cox proportional hazards models were constructed to assess the independent association with PVR.

RESULTS

Over the study period, 32,465 patients underwent HT, including 12,257 (38%) with mPAP < 25 mm Hg. The median age was 55 years (interquartile range, 47-62) and the median PVR was 1.5 Wood units (WU) (interquartile range, 1-2.2) in recipients with mPAP < 25 mm Hg. After controlling for confounders, PVR was independently associated with increased risk for 30-day mortality (hazard ratio, 1.16; 95% CI, 1.05-1.27; P < .01), but not conditional 1-year mortality (hazard ratio, 1.03; 95% CI, 0.94-1.12; P = .55). PVR ≥ 3 WU was associated with an absolute 1.9% increase in 30-day mortality in those with mPAP < 25 mm Hg, a similar risk to recipients with PVR ≥ 3 WU and mPAP ≥ 25 mm Hg.

CONCLUSIONS

Elevated PVR remains associated with a significant increase in the hazard for 30-day mortality after cardiac transplantation, even in the setting of lower pulmonary artery pressures. These data support the validity of the new definition of pulmonary hypertension.