Correlating oxygen delivery on cardiopulmonary bypass with Society of Thoracic Surgeons outcomes following cardiac surgery.

BACKGROUND: The relationship between low oxygen delivery (DO2) on cardiopulmonary bypass and morbidity and mortality following cardiac surgery remains unexamined. METHODS: We reviewed patients undergoing Society of Thoracic Surgeons index procedures from March 2019 to July 2020, coincident with implementation of a new electronic perfusion record that provides for continuous recording of DO2 and flow parameters. Continuous perfusion variables were analyzed using area-over-the-curve (AOC) calculations below predefined thresholds (DO2 <280 mL O2/min/m2, cardiac index <2.2 L/min, hemoglobin < baseline, and mean arterial pressure <65 mm Hg) to quantify depth and duration of potentially harmful exposures. Multivariable logistic regression adjusted by Society of Thoracic Surgeons predicted-risk scores were used to assess for relationship of perfusion variables with the primary composite outcome of any Society of Thoracic Surgeons index procedure, as well as individual Society of Thoracic Surgeons secondary outcomes (eg, mortality, renal failure, prolonged ventilation >24 hours, stroke, sternal wound infection, and reoperation). RESULTS: Eight hundred thirty-four patients were included; 42.7% (356) underwent isolated coronary artery bypass grafting (CABG), whereas 57.3% underwent nonisolated CABG (eg, valvular or combined CABG/valvular operations). DO2 <280-AOC trended toward association with the primary outcome across all cases (P = .07), and was significantly associated for all nonisolated CABG cases (P = .02)-more strongly than for cardiac index <2.2-AOC (P = .04), hemoglobin <7-AOC (P = .51), or mean arterial pressure <65-AOC (P = .11). Considering all procedures, DO2 <280-AOC was independently associated prolonged ventilation >24 hours (P = .04), an effect again most pronounced in nonisolated-CABG cases (P = .002), as well as acute kidney injury <72 hours (P = .04). Patients with glomerular filtration rate <65 mL/min and baseline hemoglobin <12.5 g/dL appeared especially vulnerable. CONCLUSIONS: Low DO2 on bypass may be associated with morbidity/mortality following cardiac surgery, particularly in patients undergoing nonisolated CABG. These results underscore the importance of goal-directed perfusion strategies.

Dynamic Volumetric Assessment of the Aortic Root: The Influence of Bicuspid Aortic Valve Competence.

BACKGROUND: Aortic root evaluation is conventionally based on 2-dimensional measurements at a single phase of the cardiac cycle. This work presents an image analysis method for assessing dynamic 3-dimensional changes in the aortic root of minimally calcified bicuspid aortic valves (BAVs) with and without moderate to severe aortic regurgitation. METHODS: The aortic root was segmented over the full cardiac cycle in 3-dimensional transesophageal echocardiographic images acquired from 19 patients with minimally calcified BAVs and from 16 patients with physiologically normal tricuspid aortic valves (TAVs). The size and dynamics of the aortic root were assessed using the following image-derived measurements: absolute mean root volume and mean area at the level of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction, as well as normalized root volume change and normalized area change of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction over the cardiac cycle. RESULTS: Normalized volume change over the cardiac cycle was significantly greater in BAV roots with moderate to severe regurgitation than in normal TAV roots and in BAV roots with no or mild regurgitation. Aortic root dynamics were most significantly different at the mid-level of the sinuses of Valsalva in BAVs with moderate to severe regurgitation than in competent TAVs and BAVs. CONCLUSIONS: Echocardiographic reconstruction of the aortic root demonstrates significant differences in dynamics of BAV roots with moderate to severe regurgitation relative to physiologically normal TAVs and competent BAVs. This finding may have implications for risk of future dilatation, dissection, or rupture, which warrant further investigation.

The "Ice Age" in Cardiac Surgery: Evolution of the "Siberian" Method of Brain Protection During Deep Hypothermic Perfusionless Circulatory Arrest.

Deep hypothermic perfusionless circulatory arrest was the first practical neuroprotective technique used for open-heart surgery. It was refined at the Novosibirsk Medical Research Center in Siberia and was actively used from the mid-1950s until 2001.This review describes the development of this technique and its contribution to our understanding of the dynamic changes in human physiology during induced hypothermia for circulatory arrest without extracorporeal perfusion. Deep hypothermic perfusionless circulatory arrest was an important stepping stone in the development of modern approaches in neuroprotection and monitoring during cardiac surgery.

Aortic Regurgitation in Acute Type-A Aortic Dissection: A Clinical Classification for the Perioperative Echocardiographer in the Era of the Functional Aortic Annulus.

The functional aortic annulus offers a clinical approach for the perioperative echocardiographer to classify the mechanisms of aortic regurgitation in acute type-A dissection. Comprehensive examination of the functional aortic annulus in this setting using transesophageal echocardiography can guide surgical therapy for the aortic root by considering the following important aspects: severity and mechanism of aortic regurgitation, extent of root dissection, and the pattern of coronary artery involvement. The final choice of surgical therapy also should take into account factors, such as patient presentation and surgical experience, to limit mortality and morbidity from this challenging acute aortic syndrome. This review explores these concepts in detail within the framework of the functional aortic annulus, detailed anatomic considerations, and the latest literature.

Stroke After Transcatheter Aortic Valve Replacement: Incidence, Definitions, Etiologies and Management Options.

Neurologic complications after transcatheter aortic valve replacement are devastating. The etiologies of stroke in this setting are best addressed in an integrated fashion during each phase of the perioperative pathway. The conduct of this triphasic approach will continue to be refined to reduce the stroke risks even further, given the major focus on aspects such as embolic protection devices and valve thrombosis. This neurologic focus in transcatheter aortic valve replacement has transformed the investigational approach to neurologic events in cardiovascular clinical trials, resulting in novel guidelines for the diagnosis and assessment of neurologic injury after cardiovascular interventions.