Comparative assessment of coronary physiology using transthoracic pulsed-wave Doppler and myocardial contrast echocardiography in rats.

BACKGROUND: Coronary physiology assessment in rodents by ultrasound is an excellent noninvasive and easy to perform technique, including pulsed-wave Doppler (PWD) and myocardial contrast echocardiography (MCE). Both techniques and the corresponding calculated parameters were investigated in this study at rest as well as their response to pharmacologically induced stress. METHODS: Left ventricular myocardial function was assessed in eight anaesthetised rats using transthoracic echocardiography. Coronary physiology was assessed by both PWD of the left coronary artery and MCE using a bolus method. Measurements were performed at rest and under stimulation with adenosine and dobutamine. Effects of stimulation on the calculated parameters were evaluated and rated by effect size (η2). RESULTS: Changes could be demonstrated by selected parameters of PWD and MCE. The clearest effect in PWD was found for diastolic peak velocity (η2 = 0.58). It increased from 528 ± 110 mm/s (mean ± standard deviation) at rest to 839 ± 342 mm/s (p = 0.001) with adenosine and 1093 ± 302 mm/s with dobutamine (p = 0.001). The most distinct effect from MCE was found for the normalised wash-in rate (η2 = 0.58). It increased from 1.95 ± 0.35% at rest to 3.87 ± 0.85% with adenosine (p = 0.001) and 3.72 ± 1.03% with dobutamine (p = 0.001). CONCLUSION: Induced changes in coronary physiology by adenosine and dobutamine could successfully be monitored using MCE and PWD in anaesthetised rats. Due to the low invasiveness of the measurements, this protocol could be used for longitudinal animal studies.

Visual quality assessment of the liver graft by the transplanting surgeon predicts postreperfusion syndrome after liver transplantation: a retrospective cohort study.

BACKGROUND: The discrepancy between demand and supply for liver transplants (LT) has led to an increased transplantation of organs from extended criteria donors (ECD). METHODS: In this single center retrospective analysis of 122 cadaveric LT recipients, we investigated predictors of postreperfusion syndrome (PRS) including transplant liver quality categorized by both histological assessment of steatosis and subjective visual assessment by the transplanting surgeon using multivariable regression analysis. Furthermore, we describe the relevance of PRS during the intraoperative and postoperative course of LT recipients. RESULTS: 53.3% (n = 65) of the patients suffered from PRS. Risk factors for PRS were visually assessed organ quality of the liver grafts (acceptable: OR 12.2 [95% CI 2.43-61.59], P = 0.002; poor: OR 13.4 [95% CI 1.48-121.1], P = 0.02) as well as intraoperative norepinephrine dosage before reperfusion (OR 2.2 [95% CI 1.26-3.86] per 0.1 µg kg- 1 min- 1, P = 0.01). In contrast, histological assessment of the graft was not associated with PRS. LT recipients suffering from PRS were hemodynamically more instable after reperfusion compared to recipients not suffering from PRS. They had lower mean arterial pressures until the end of surgery (P < 0.001), received more epinephrine and norepinephrine before reperfusion (P = 0.02 and P < 0.001, respectively) as well as higher rates of continuous infusion of norepinephrine (P < 0.001) and vasopressin (P = 0.02) after reperfusion. Postoperative peak AST was significantly higher (P = 0.001) in LT recipients with PRS. LT recipients with intraoperative PRS had more postoperative adverse cardiac events (P = 0.05) and suffered more often from postoperative delirium (P = 0.04). CONCLUSIONS: Patients receiving ECD liver grafts are especially prone to PRS. Anesthesiologists should keep these newly described risk factors in mind when preparing for reperfusion in patients receiving high-risk organs.