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.

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.

Characterization of intentional lurasidone ingestions using the United States National Poison Data System

Introduction: The ziprasidone analogue lurasidone is approved for the treatment of schizophrenia and bipolar disorder for adults and children older than 10 years. Small studies and case reports suggest lurasidone overdose is not generally associated with major adverse effects, but no large sample has been published.Objective: To describe intentional lurasidone overdoses reported to poison centers.Methods: Retrospective analysis of single-substance intentional lurasidone ingestions from the National Poison Data System (NPDS) from 2011 to 2018.Results: There were 1753 single-substance intentional overdoses. Average age was 28.6 years (SD = 13.3 years) and 1199 (68.4%) of patients were female. Most cases (86.6%) were coded as suspected suicide. Regarding final management site, 1143 (65.2%) were discharged or admitted to psychiatric facilities; 328 (18.8%) were admitted, half of whom were admitted to critical care units (CCUs). Major effect was coded in 12 (0.7%), moderate effect in 259 (14.8%), minor effect in 531 (30%), and no effect in 614 (35%). There were no deaths. For cases for which dose information was available, there was not a statistically significant difference between median doses when analyzed by clinical effect. Most common adverse effects were drowsiness (449, 25.6%), tachycardia (254, 14.5%), vomiting (121, 6.9%), and hypertension (115, 6.6%). Most cases had either no therapy reported, or therapy was recommended by the poison center but confirmed not to have been administered (1010, 57.6%). Of the 164 patients admitted to CCUs, 80 (48.8%) received either no therapy or intravenous fluids alone.Discussion: These data suggest major effects are uncommon from lurasidone overdose. Despite a high rate of admission to CCUs, a substantial proportion received no critical therapies.Conclusions: This report demonstrates intentional lurasidone overdoses reported to poison centers generally have a favorable clinical course.

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.

Sodium bicarbonate use and the risk of hypernatremia in thoracic aortic surgical patients with metabolic acidosis following deep hypothermic circulatory arrest

Objective:

Metabolic acidosis after deep hypothermic circulatory arrest (DHCA) for thoracic aortic operations is commonly managed with sodium bicarbonate (NaHCO₃). The purpose of this study was to determine the relationships between total NaHCO₃ dose and the severity of metabolic acidosis, duration of mechanical ventilation, duration of vasoactive infusions, and Intensive Care Unit (ICU) or hospital length of stay (LOS).

Methods:

In a single center, retrospective study, 87 consecutive elective thoracic aortic operations utilizing DHCA, were studied. Linear regression analysis was used to test for the relationships between the total NaHCO₃ dose administered through postoperative day 2, clinical variables, arterial blood gas values, and short-term clinical outcomes.

Results:

Seventy-five patients (86%) received NaHCO₃. Total NaHCO₃ dose averaged 136 ± 112 mEq (range: 0.0–535 mEq) per patient. Total NaHCO₃ dose correlated with minimum pH (r = 0.41, P < 0.0001), minimum serum bicarbonate (r = −0.40, P < 0.001), maximum serum lactate (r = 0.46, P = 0.007), duration of metabolic acidosis (r = 0.33, P = 0.002), and maximum serum sodium concentrations (r = 0.29, P = 0.007). Postoperative hypernatremia was present in 67% of patients and peaked at 12 h following DHCA. Eight percent of patients had a serum sodium ≥ 150 mEq/L. Total NaHCO₃ dose did not correlate with anion gap, serum chloride, not the duration of mechanical ventilator support, vasoactive infusions, ICU or hospital LOS.

Conclusion:

Routine administration of NaHCO₃ was common for the management of metabolic acidosis after DHCA. Total dose of NaHCO₃ was a function of the severity and duration of metabolic acidosis. NaHCO₃ administration contributed to postoperative hypernatremia that was often severe. The total NaHCO₃ dose administered was unrelated to short-term clinical outcomes.