Original articles
Alterations of mesenteric blood flow after cardiopulmonary bypass: A Doppler sonographic study

https://doi.org/10.1053/j.jvca.2004.08.010Get rights and content

Abstract

Objective: Mesenteric ischemia after cardiopulmonary bypass is a serious complication associated with high mortality. It was the aim of this study to investigate mesenteric blood flow with the help of Doppler sonography in asymptomatic patients before and after cardiopulmonary bypass and cardiac surgery.

Design: Observational study of consecutive patients.

Setting: Nonuniversity cardiac center.

Participants: Twenty-five patients undergoing elective coronary revascularization with normal left ventricular function and stable postoperative circulations with no need for catecholamines.

Measurements and Main Results: Preoperative and postoperative color and CW-Doppler sonography of the superior mesenteric artery. Diameter of the superior mesenteric artery and the Doppler flow profile were analyzed. Preoperative and postoperative hemodynamic data were measured by using a pulmonary artery thermodilution catheter. Mesenteric systolic flow velocity was 135 ± 11 cm/s preoperatively and 193 ± 13 cm/s postoperatively (p < 0.05). The corresponding preoperative and postoperative values of diastolic flow velocity were 14 ± 4 and 4 ± 2 cm/s (p < 0.05) and the values of mean flow velocity were 24 ± 3 and 17 ± 2 cm/s (p < 0.05), respectively. The preoperative Pourcelot resistive index was 0.87 ± 0.05, and the preoperative Gosling pulsatility index was 4.6 ± 0.5. Both indices increased postoperatively to values of 0.98 ± 0.04 and 9.5 ± 0.7, respectively (p < 0.05). Preoperative and postoperative hemodynamic data did not differ significantly.

Conclusion: The postoperative changes in the flow velocities and the increases of the resistive and pulsatility index are indications of rigidity of the mesenteric vascular bed and decreased mesenteric perfusion after cardiopulmonary bypass.

Section snippets

Material and methods

Thirty patients who underwent coronary artery bypass grafting were studied. This series consisted of 22 men and 8 women with a mean age of 63 ± 8 years. Preoperative left ventricular function was normal in all patients (ejection fraction 74% ± 11%). Preoperative and postoperative Duplex and color-flow Doppler evaluations of the superior mesenteric artery were performed 30 minutes after induction of anesthesia for preoperative values and 60 minutes after end of surgery for postoperative values,

Results

In 5 of 30 patients, sonographic investigation was not possible because of poor visualization of the superior mesenteric artery. In the remaining 25 patients, sufficient visualization of the superior mesenteric artery could be achieved to obtain proper Doppler signals.

The mean CPB and cross-clamp times were 94 ± 19 and 39 ± 14 minutes, respectively, and no significant differences could be found between preoperative and postoperative values of cardiac output (5.4 ± 0.8 v 5.1 ± 0.6 L/min),

Discussion

Gastrointestinal complications are rare after cardiac surgery, arising in 0.5% to 3.0% of patients, and the proportion of those suffering from mesenteric ischemia is reported to be 11% to 30%.1, 2 Gut ischemia is reported with an incidence of 0.07% to 0.60%.3, 4, 6, 7 In 1978, Aakhus and Evensen5 first showed the benefit of arteriography in diagnosing splanchnic ischemia. They further described a treatment option for mesenteric arterial spasm by the injection of tolazoline through the

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