Coronary Artery Surgery Study (CASS)

February 16, 2016 updated by: University of Washington
To compare coronary artery surgery with medical management in patients with coronary artery disease and to maintain a registry on all patients undergoing coronary arteriography, whether operatively or medically managed.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

BACKGROUND:

Although it was generally agreed that many patients with severe angina pectoris improved symptomatically after coronary artery surgery, there was less consensus concerning, for example, other effects of the procedure, such as its long-term benefit and the criteria for patient selection. In addition, there were fewer data and less agreement on the effects and proper role of this procedure in other clinical circumstances. Both the surgical procedure and the prior diagnostic procedures represented substantial costs in both monetary and manpower terms; moreover, they entailed morbidity and mortality risks.

There existed an urgent need for reliable and quantitative information regarding the effects of coronary artery surgery in patients with ischemic heart disease. To be meaningful, these data had to be set into the perspective of the clinical course of such patients under medical treatment.

This assessment presupposed a meaningful classification of these patients and of the therapeutic interventions as well as evaluations of the effects of surgical and medical regimens in terms of mortality, the quality of life, and objective hemodynamic and other physiological measurements. Only such information could provide sufficient background for determining the suitability of coronary artery surgery for a particular patient.

In 1972, the National Heart and Lung Advisory Council identified these questions as topics of high priority, and the National Heart and Lung Institute established an Ad Hoc Policy Advisory Board on Coronary Artery Surgery to assist it in developing a program of research activities. In its report, the Board noted a 'critical need for objective data on the long- and short-term effects of coronary artery surgery.' Requests for proposals were issued to carry out the recommendations of the Board.

Planning of the trial was conducted between June 1973 and April 1975 and included protocol design, the development of a manual of operations, and a pilot study of the registry. In August 1975, registry patients' entry and randomization began at the 11 clinical centers and coordinating center. Initial projections of patient population numbers were underestimated; therefore, five clinical centers were added to the trial in 1976.

The five clinical subgroups of patients in the randomized studies included: stable angina with normal resting left ventricular function; stable angina with impaired left ventricular function; post-myocardial infarction without angina; congestive heart failure due primarily to ischemic heart disease; and patients previously asymptomatic who were discovered to have serious coronary artery disease. All of the above subgroups must have met specifically outlined clinical and angiographic criteria to be placed in the randomized subset. The other two subsets (as distinguished from subgroups) of the study included those patients who were unsuitable for randomization because surgery was the treatment of choice in the judgment of many physicians and those patients for whom medical management was the treatment of choice. The patients enrolled in both the registry and randomized trial were followed for a 10-year period. This allowed evaluation of the primary endpoints, death and myocardial infarction, and the secondary endpoints, angina, status, and quality of life.

A total of 24,959 patients were entered into the registry; 780 patients were entered into the trial. Recruitment ended in 1979. Intervention ended in June 1983. Follow-up was extended for an additional five years to June 1989. Data analysis continued through May 1995 with grant support.

DESIGN NARRATIVE:

Randomized, non-blind, sequential. Some 780 patients meeting the criteria of specific subsets based on history, physical exam, laboratory tests, catheterization, and angiography were randomized to either surgical or medical therapy. Primary endpoints included death and myocardial infarction.

Study Type

Interventional

Phase

  • Phase 3

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

21 years to 66 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Men and women, under 67 years old. Ischemic heart disease.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Washington

Collaborators

National Heart, Lung, and Blood Institute (NHLBI)

Investigators

  • Kathryn Davis, University of Washington

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

June 1, 1973

Study Completion

December 1, 1996

Study Registration Dates

First Submitted

October 27, 1999

First Submitted That Met QC Criteria

October 27, 1999

First Posted (Estimate)

October 28, 1999

Study Record Updates

Last Update Posted (Estimate)

February 18, 2016

Last Update Submitted That Met QC Criteria

February 16, 2016

Last Verified

December 1, 2005

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 8
  • R01HL038941 (U.S. NIH Grant/Contract)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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