Pharmacological vs. mechanical reduction in portal pressure: a comparative study

Area of Science:

• Cardiovascular Physiology
• Gastroenterology
• Surgical Innovation

Background:

• Decreasing superior mesenteric artery (SMA) blood flow can alter splanchnic and systemic hemodynamics.
• Intra-arterial vasopressin and partial balloon obstruction of the SMA are two methods to reduce SMA blood flow.

Purpose of the Study:

• To compare the splanchnic and systemic hemodynamic effects of intra-arterial vasopressin versus partial balloon obstruction of the SMA.
• To evaluate the safety and efficacy of prolonged partial balloon obstruction of the SMA.

Main Methods:

• Six anesthetized dogs underwent both vasopressin infusion and partial balloon obstruction of the SMA to compare hemodynamic changes.
• Five additional dogs had prolonged partial balloon obstruction of the SMA for 5 hours to assess sustained effects and safety.

Main Results:

• Both methods similarly reduced portal pressure, wedge hepatic vein pressure, and portal venous flow.
• Partial balloon obstruction increased cardiac output and heart rate, and decreased systemic vascular resistance, unlike vasopressin which decreased cardiac output and heart rate, and increased systemic vascular resistance.
• Prolonged partial balloon obstruction maintained reduced portal venous pressure and mean arterial pressure without adverse effects or intestinal damage.

Conclusions:

• Partial balloon obstruction of the SMA is as effective as vasopressin in reducing portal pressure and flow.
• Partial balloon obstruction avoids the potentially harmful systemic hemodynamic changes associated with vasopressin infusion.
• Partial balloon obstruction of the SMA presents a potentially advantageous therapeutic option for managing portal venous pressure.