Intraoperative Simultaneous Pressure Guided Revascularization Study (INSTANT)

This study aims to determine whether intraoperative physiologic measurements of blood flow to the leg during endovascular treatment of Peripheral Arterial Disease (PAD) can predict future clinical outcomes.

Study Overview

• Status: Completed
• Conditions: Peripheral Vascular Diseases; Blood Pressure; Endovascular Procedures; Clinical Decision-Making; Monitoring, Intraoperative
• Intervention / Treatment: Diagnostic test: Intraoperative Hemodynamic Pressures; Diagnostic test: Contrast Flow Rate

Detailed Description

Lower extremity peripheral arterial disease (PAD) caused by atherosclerosis can cause cause leg pain, gangrene, and limb loss. PAD is a result of poor blood flow to the extremity, and the emerging most common initial method of interventional treatment is endovascular therapy, for example angioplasty or stenting. The poor blood flow to the extremity can be inferred by the hemodynamic pressure of blood in the leg. These toe or ankle pressure measurements are typically performed before surgery to diagnose PAD, and after surgery as surveillance.

However, endovascular treatment has a high failure rate often exceeding 20% within a year. There is evidence that physiologic measurements prior to treatment and after treatment are closely related to clinical outcomes. This study introduces these physiologic measurements to the operating room, to determine if physiologic improvement can be detected instantaneously during endovascular revascularization. Patients will be followed for a year following surgery to detect hemodynamic and clinical outcomes. The rationale of these intraoperative measurements would be to potentially guide future surgery, by providing real-time hemodynamic feedback to the operator.

• Study Type: Observational
• Enrollment (Actual): 80

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Ottawa, Ontario, Canada, K1Y 4E9
      • The Ottawa Hospital, Civic Campus

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients undergoing elective or semi-urgent endovascular procedures for lower extremity de-novo atherosclerotic peripheral vascular disease. These patients will be treated at The Ottawa Hospital, Civic Campus, under the care of the Division of Vascular Surgery.

Description

Inclusion Criteria:

• Patients undergoing elective or semi-urgent endovascular procedures on lesions of the aorta, iliac, femoral, popliteal, or tibial arteries
• Symptomatic, atherosclerotic Peripheral Vascular Disease. These symptoms include any Rutherford's classification.

Exclusion Criteria:

• Concurrent hybrid open procedure during endovascular revascularization requiring vascular clamping for any period of time, such as endarterectomy
• Prior open vascular surgery performed on the affected leg
• Emergent intervention for Acute Limb Ischemia, defined as symptoms lasting less than 14 days
• Non-femoral vascular access

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Intraoperative Hemodynamic Improvement; The primary outcome will examine the magnitude of change in the Toe-Brachial Index (TBI) between the beginning and the end of the procedure. The two measurements will be taken before- and after- vascular sheaths had been placed.

Diagnostic test: Intraoperative Hemodynamic Pressures; Secondary analyses will examine the Ankle-Brachial Index, and the absolute limb pressures. In addition, the changes in flow rate of contrast before- and after- intervention will be examined as an indicator of perfusion.; Other Names: Toe Brachial Index; Ankle Brachial Index; Absolute Toe Pressure; Absolute Ankle Pressure; Diagnostic test: Contrast Flow Rate; A secondary analysis will examine the rate of contrast flow during pre-intervention and post-intervention angiograms, and correlate these findings with hemodynamic measurements recorded during surgery.; Other Names: Time to Peak Opacification; Rate of Contrast Opacification; Wash-In Rate; Wash-Out Rate

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Major Adverse Limb Event (MALE)	Composite outcome of major amputation above the ankle, major re-intervention in the form of catheter-directed thrombolysis, open bypass or thrombectomy.	1 Year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Major Amputation	Any ipsilateral leg amputation performed above the joint of the ankle.	1 Year
Minor Amputation	Any ipsilateral leg amputation performed distal to the joint of the ankle.	1 Year
Target Vessel Re-Intervention	Endovascular, Open, Thrombectomy, Thrombolysis.	1 Year
Target Vessel Patency	Primary: Absence of target vessel occlusion or restenosis >50% Primary Assisted: Patency requiring assistance of subsequent procedure to maintain patency of target vessel Secondary: Patency requiring assistance of subsequent procedure to restore patency of target vessel	1 Year
Improvement in Rutherford's Classification of Peripheral Vascular Disease	Maximal documented categorical state following index revascularization	1 Year
Post-Operative Hemodynamic Measurements	Correlation between intraoperative completion and immediate post-operative measurements, with longer-term surveillance measurements	1 - 3 Months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mortality	As captured by the hospital's Electronic Health Record	1 Year
Amputation-Free Survival	Survival free of major amputation.	1 Year

Collaborators and Investigators

• Sponsor: Mark Rockley
• Investigators: Principal Investigator: George Wells, PhD, MSc, Cardiovascular Research Methods Centre, University of Ottawa Heart Institute

Publications and helpful links

General Publications

• Rockley M, Jetty P, Wells GA. Protocol for a prospective observational diagnostic study: intraoperative simultaneous limb pressure monitoring (INSTANT) study. BMJ Open. 2019 Aug 22;9(8):e030456. doi: 10.1136/bmjopen-2019-030456.

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2018
• Primary Completion (Actual): January 1, 2020
• Study Completion (Actual): January 1, 2021

Study Registration Dates

• First Submitted: March 13, 2019
• First Submitted That Met QC Criteria: March 13, 2019
• First Posted (Actual): March 15, 2019

Study Record Updates

• Last Update Posted (Actual): August 4, 2021
• Last Update Submitted That Met QC Criteria: August 2, 2021
• Last Verified: August 1, 2021

More Information

Terms related to this study

• Keywords: Revascularization; Intraoperative Decision Making; Physiologic Monitoring Feedback
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Atherosclerosis; Vascular Diseases; Peripheral Arterial Disease; Peripheral Vascular Diseases
• Other Study ID Numbers: 20180656-01H

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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