Christine Herman

Intraoperative graft flow measurements during coronary artery bypass surgery predict in-hospital outcomes

Transit-time flowmetry enables immediate intraoperative assessment of blood flow parameters in coronary artery bypass grafts (CABG). The present study assesses the predictive value of measured graft flows on early and medium-term outcomes. All cardiac surgery patients with measured graft flows were included. The last intraoperative flow measurements recorded using the Medtronic Butterfly Flowmetry system were used for analysis. Patients were separated into two groups: patients with normal flow in all grafts or patients with abnormal flow > or =1 graft. Any pulsatility index (pulsatility index=min-max flow/mean flow) < or =5 was determined to be normal flow. The study population included 985 patients. Nineteen percent of patients had abnormal flow in > or =1 graft. Overall in-hospital mortality was 4.7% and not significant between the two groups. After adjusting for covariates, the in-hospital composite outcome for adverse cardiac events was more prevalent in the abnormal flow group (31% vs. 17%; P<0.0001) with an odds ratio of 1.7 (CI 1.1-2.7). Survivors to discharge had a mean follow-up of 1.8 years. However, abnormal flow was not an independent predictor of the medium-term mortality and readmission to hospital for cardiac reason following discharge. Our findings suggest that abnormal flows measured intraoperatively are independently associated with short-term in-hospital adverse outcome.

Development of a predictive model for major adverse cardiac events in a coronary artery bypass and valve population

BackgroundQuality improvement initiatives in cardiac surgery largely rely on risk prediction models. Most often, these models include isolated populations and describe isolated end-points. However, with the changing clinical profile of the cardiac surgical patients, mixed populations models are required to accurately represent the majority of the surgical population. Also, composite model end-points of morbidity and mortality, better reflect outcomes experienced by patients.MethodsThe model development cohort included 4,270 patients who underwent aortic or mitral valve replacement, or mitral valve repair with/without coronary artery bypass grafting, or isolated coronary artery bypass grafting. A composite end-point of infection, stroke, acute renal failure, or death was evaluated. Age, sex, surgical priority, and procedure were forced, a priori, into the model and then stepwise selection of candidate variables was utilized. Model performance was evaluated by concordance statistic, Hosmer-Lemeshow Goodness of Fit, and calibration plots. Bootstrap technique was employed to validate the model.ResultsThe model included 16 variables. Several variables were significant such as, emergent surgical priority (OR 4.3; 95% CI 2.9-7.4), CABG + Valve procedure (OR 2.3; 95% CI 1.8-3.0), and frailty (OR 1.7; 95% CI 1.2-2.5), among others. The concordance statistic for the major adverse cardiac events model in a mixed population was 0.764 (95% CL; 0.75-0.79) and had excellent calibration.ConclusionsDevelopment of predictive models with composite end-points and mixed procedure population can yield robust statistical and clinical validity. As they more accurately reflect current cardiac surgical profile, models such as this, are an essential tool in quality improvement efforts.

SS28. Long-Term Survival After Endovascular Repair and Open Repair in Patients With Anatomy Outside Endovascular Repair Indications for Use Criteria

nonischemic part (proximal). After tissue processing, the cDNA was then used in reverse transcriptase polymerase chain reaction using Bio-Rads Prime PCR Probe Assays and IL-6, NOSTRIN, PROM1 and VEGFA gene expression were measured. Results: A paired t test was run for each set of data to determine whether the difference in expression levels between nonischemic (proximal) and ischemic tissues (distal) were significantly different (Fig). None of the comparisons was statistically significant. However, arterial VEGFA expression was higher in the ischemic compared with nonischemic tissues and seemed to be trending toward significance with a P value of .1. On the other hand, IL6 expression was higher in the nonischemic compared with ischemic tissues (P 1⁄4 .2). Conclusions: This study showed an increase in the VEGFA expression by the arterial MSCs in ischemic tissues which might indicate an attempt of the arterial MSCs to stimulate angiogenesis and vasculogenesis in the setting of ongoing ischemia. However, a larger sample size is needed to reach statistical significance.

Surgically Positioned Paravertebral Catheters and Postoperative Analgesia After Open Abdominal Aortic Aneurysm Repair

Results: The Ottawa Hospital experienced a 61% decline in the number of OARs performed between 2005 and 2016. Age of participants was significantly increased in the 2014 to 2017 group (P 1⁄4 .0141), whereas the number of women was significantly decreased (P 1⁄4 .05). Total operating room time and anesthesia time were longer in the 2014 to 2017 group, whereas surgical times remained consistent. Suprarenal clamp time and blood loss during the procedure were decreased in the 2014 to 2017 group. Intensive care unit and overall hospital stay were not significantly different between groups; however, there were large standard deviations observed for the 2014 to 2017 group. As well, 18.4% of patients in the 2014 to 2017 group experienced postsurgical complications of Clavien-Dindo grade IIIa or higher compared with 11.3% of patients in the historical control group. Mortality was increased in the 2014 to 2017 group, although this was not significant. Conclusions: The reduced rate of OAR performance at The Ottawa Hospital reflects the global trend toward endovascular repair. Anesthesia and operating room time increased during the time examined, reflecting a possible loss of expertise in the study period. Complications also increased during this time for anatomically similar patients. Taken together, these findings may reflect a decreased institutional familiarity with open aneurysm repairs and postsurgical care.

Intraoperative insertion of paravertebral catheter for postoperative analgesia in retroperitoneal aortic aneurysm repair

ABSTRACT Paravertebral catheters are a well‐established analgesic modality in thoracic surgery but have not been described in abdominal aortic surgery. We describe a simple, safe, and effective technique of paravertebral catheter insertion by the operative surgeon after a retroperitoneal abdominal aortic aneurysm repair. Once the aneurysm repair is complete, an extrapleural plane between the parietal pleura and the twelfth rib is created through blunt dissection. A catheter is advanced into the space percutaneously under direct vision, and a continuous infusion of local anesthetic is administered. Paravertebral catheters typically remain in place for 3 to 5 days and provide excellent postoperative non‐narcotic analgesia.

Cerebral embolic protection during endovascular arch replacement

Despite excellent results in high volume centers, open repair of aortic arch pathology is highly invasive, and can result in significant morbidity and mortality in high risk patients. Near-total and hybrid approaches to aortic arch disease states have emerged as an alternative for patients deemed moderate to high risk for conventional repair. Advantages of these approaches include avoidance of extracorporeal circulation and hypothermic circulatory arrest as well as avoidance of cross clamping, all of which are not well tolerated in high risk patients. Anatomically high-risk patients with anastomotic aneurysms from previous arch reconstruction may also benefit from these less invasive approaches. Medical devices designed specifically for the aortic arch are developing at a rapid pace and continue to evolve. Dedicated devices for zone 0-2 aortic arch repair are currently available under special access or being studied in clinical trials. Unfortunately, stroke continues to be the Achilles heel of endovascular approaches to the aortic arch, with cerebral embolism being the culprit in the majority of such cases. This perspective article describes the epidemiology, procedures, and mitigation strategies for current near-total and hybrid approaches to aortic arch pathology, and specifically addresses current means of embolic protection and future direction.

Salvage of bilateral renal artery occlusion after endovascular aneurysm repair with open splenorenal bypass

We report renal salvage maneuvers after accidental bilateral renal artery coverage during endovascular aneurysm repair of an infrarenal abdominal aortic aneurysm. A 79-year-old man with an infrarenal abdominal aortic aneurysm was treated with endovascular aneurysm repair. Completion angiography demonstrated coverage of the renal arteries. Several revascularization techniques were attempted, including endograft repositioning and endovascular stenting through the femoral and brachial approach. The patient eventually underwent open splenorenal bypass with a Y Gore-Tex graft (W. L. Gore & Associates, Flagstaff, Ariz). After 3 months, computed tomography showed no evidence of endoleak and patent renal arteries. Renal function was well maintained, and the patient did not require dialysis.