Microvascular Reactivity in Cardiac Surgery

Microvascular Reactivity as a Predictor of Major Adverse Events in Patients With On-pump Cardiac Surgery: A Prospective Observational Study

Microcirculatory disturbance occurs most seriously during cardiopulmonary bypass (CPB) in cardiac surgery. If microvascular reactivity compensates for microcirculatory disturbance during CPB, tissue hypoxemia may be minimized. On the other hand, tissue hypoxemia may develop and lead to poor clinical outcomes. The primary aim of this study was to assess whether microvascular reactivity during CPB can predict major adverse events (MAE) within 30 days after cardiac surgery.

This prospective, observational, single-center study was conducted on 115 patients who underwent elective on-pump cardiac surgery. The vascular occlusion test (VOT) with near-infrared spectroscopy was performed five times for each patient, before the induction of general anesthesia (baseline, T0), 30 min after the induction of general anesthesia (T1), 30 min after applying CPB (T2), 10 min after injection of protamine (T3), and after sternal closure (T4). Sequential Organ Failure Assessment (SOFA) and Acute Physiologic and Chronic Health Evaluation (APACHE) II scores and the length of ventilator care, intensive care unit stay, and hospital stay were recorded. Postoperative MAE within 30 days after surgery was also recorded.

Study Overview

• Status: Completed
• Conditions: Cardiac Disease
• Intervention / Treatment: Diagnostic test: vascular occlusion test

Detailed Description

The VOT was performed five times in each patient, before the induction of general anesthesia (baseline, T0), 30 min after the induction of general anesthesia (T1), 30 min after applying CPB (T2), 10 min after injection of protamine (T3), and after sternal closure (T4). Before induction of anesthesia, an NIRS sensor (INVOS® 5100C Cerebral/Somatic Oximeter; Medtronic, Minneapolis, MN, USA) was placed on the thenar eminence and an automated tourniquet (A.T.S® 3000 Automatic Tourniquet System; Zimmer Inc., Warsaw, IL, USA) was placed around the upper arm. The arterial catheter was placed in the contralateral radial artery and the baseline blood pressure was measured. When the baseline tissue oxygen saturation (StO2) was stabilized, the automatic tourniquet was inflated to 50 mmHg over the patient's baseline systolic blood pressure and maintained for 5 min. After the 5-min ischemic period, the tourniquet rapidly deflated to 0 mmHg. StO2 data were continuously recorded during the VOT procedure. Baseline StO2, minimum StO2 during the 5-min inflation of the tourniquet, and maximum StO2 during deflation of the tourniquet were obtained. The occlusion slope and recovery slope were calculated based on the measured StO2 data. The occlusion slope, which is related to oxygen extraction, was defined as the slope of the StO2 descent to the lowest value. The recovery slope, which is related to microvascular reactivity, was calculated from the deflation of the tourniquet until the recovery of StO2 to the highest value.

• Study Type: Observational
• Enrollment (Actual): 115

Contacts and Locations

Study Locations

• Korea, Republic of
  • Busan, Korea, Republic of, 49241
    • Pusan National University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 17 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Adult patients aged >18 years scheduled for elective on-pump cardiac surgery in Pusan National University Hospital.

Description

Inclusion Criteria:

• adult patients aged >18 years
• elective on-pump cardiac surgery

Exclusion Criteria:

• pregnancy
• inability to tolerate VOT (e.g., patients with arm deformities, arteriovenous shunts, burns)adult patients aged >18 years scheduled for elective on-pump cardiac surgery
• refusal to participate in the study

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recovery slope	Recovery slope is related to microvascular reactivity, was calculated from the deflation of the tourniquet until the recovery of tissue oxygen saturation to the highest value.	during applying cardiopulmonary bypass, an average 1-2 hours
Major adverse events	death, acute kidney injury, myocardial infarction, acute respiratory distress syndrome, aggravated heart failure, gastrointestinal bleeding	within postoperative 30 days

Collaborators and Investigators

• Sponsor: Pusan National University Hospital
• Investigators: Principal Investigator: Heon-Jeong Lee, PhD, Pusan National University Hospital

Study record dates

Study Major Dates

• Study Start (Actual): February 14, 2017
• Primary Completion (Actual): May 30, 2019
• Study Completion (Actual): June 28, 2019

Study Registration Dates

• First Submitted: February 10, 2021
• First Submitted That Met QC Criteria: February 16, 2021
• First Posted (Actual): February 18, 2021

Study Record Updates

• Last Update Posted (Actual): February 18, 2021
• Last Update Submitted That Met QC Criteria: February 16, 2021
• Last Verified: February 1, 2021

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Heart Diseases
• Other Study ID Numbers: 1702-003-051

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No