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ACE-inhibitors, calcium antagonists and low systemic vascular resistance following cardiopulmonary bypass. A
P S Myles1, I Olenikov, M A Bujor
1Alfred Hospital, Prahran, Vic.
Insights
Low systemic vascular resistance syndrome after cardiac surgery is not linked to ACE-inhibitor or calcium antagonist use. This finding helps clarify risk factors for this post-cardiopulmonary bypass complication.
Area of Science:
- Cardiology
- Anesthesiology
- Critical Care Medicine
Background:
- Low systemic vascular resistance (SVR) syndrome is a potential complication following cardiac surgery and cardiopulmonary bypass (CPB).
- Preoperative use of certain medications, such as angiotensin-converting enzyme (ACE) inhibitors and calcium antagonists, has been questioned as a potential contributing factor to this syndrome.
Purpose of the Study:
- To determine if there is an association between the use of ACE inhibitors or calcium antagonists and the development of low SVR syndrome after cardiac surgery and CPB.
- To investigate the incidence of low SVR syndrome in patients undergoing cardiac surgery.
Main Methods:
- A case-control study was conducted in a cardiothoracic surgical unit.
- Cases of low SVR syndrome were identified from intensive care unit charts and matched with two controls each.
- Exposure to ACE inhibitors or calcium antagonists was assessed in a blinded manner from patient medical records.
Main Results:
- No significant association was found between the use of ACE inhibitors and low SVR syndrome (OR, 1.33; 95% CI, 0.53-3.34).
- No significant association was found between the use of calcium antagonists and low SVR syndrome (OR, 0.49; 95% CI, 0.21-1.13).
- The overall incidence of low SVR syndrome was 7.4%; affected patients required more vasopressor support and had longer ICU stays.
Conclusions:
- Preoperative use of ACE inhibitors or calcium antagonists is not associated with an increased risk of developing low SVR syndrome following cardiopulmonary bypass.
- The findings suggest that other factors likely contribute to the development of low SVR syndrome in the post-cardiac surgery period.
Objective:
To investigate whether the syndrome of low systemic vascular resistance (SVR) following cardiac surgery and cardiopulmonary bypass (CPB) is more common in patients taking angiotensin-converting enzyme inhibitors (ACE-inhibitors) or calcium antagonists.
Design:
A case-control study, with cases ("low SVR syndrome") identified from intensive care unit observation charts. These cases were each matched to two controls identified from the same group of charts during the same time period. Exposure (ACE-inhibitors or calcium antagonists) was determined in a blinded fashion from the patient's medical record.
Setting:
Cardiothoracic surgical unit in a teaching hospital.
Participants:
We identified 42 cases of low SVR syndrome; these were matched to 84 controls.
Results:
There was no association between therapy with ACE-inhibitors and the low SVR syndrome following CPB (odds ratio [OR], 1.33; 95% confidence interval [CI], 0.53-3.34), nor with calcium antagonists (OR, 0.49; 95% CI, 0.21-1.13). The incidence of the low SVR syndrome was 7.4%. Patients who develop the low SVR syndrome are more likely to be treated with noradrenaline, adrenaline and dopamine, and spend more time in the cardiothoracic intensive care unit.
Conclusion:
The "low SVR syndrome" following CPB is not associated with preoperative therapy with ACE-inhibitors or calcium antagonists.