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Quantitation of ischemia during total coronary occlusion with computer-assisted high resolution ST-segment
R K Bottner1, C J Morea, C R Green
1Georgetown University Hospital, Washington, D.C.
Insights
Good collateral flow during transluminal coronary angioplasty (TCA) significantly reduces ischemia and angina. However, this protective effect diminishes after the procedure, suggesting collateral inadequacy.
Area of Science:
- Cardiology
- Interventional Cardiology
- Myocardial Ischemia Research
Background:
- Collateral circulation plays a crucial role in myocardial perfusion.
- Assessing the impact of collateral flow on ischemia during percutaneous coronary interventions is vital.
Purpose of the Study:
- To evaluate the effect of collateral flow on clinical and electrocardiographic signs of ischemia during transluminal coronary angioplasty (TCA).
Main Methods:
- 118 patients undergoing TCA were assessed using a qualitative collateralization scoring system (0-3).
- Computerized ST-segment monitoring and recording of chest pain episodes were performed.
- Ischemic ST-segment response was defined as 1.0 mm deviation from baseline.
Main Results:
- Patients with collateral filling (scores 2-3) had significantly lower rates of angina (42%) and ischemic ST changes (15%) compared to those without (83% and 74%).
- Ischemic ST-segment responses occurred in 58% of patients without collateral filling versus 9% with collateral filling during balloon inflation (p < .0001).
- Post-TCA, angina and ischemic ST changes were similar in both groups, indicating potential late inadequacy of collateral flow.
Conclusions:
- Increasing collateralization provides protection against myocardial ischemia during TCA.
- The similar incidence of late ischemia suggests that collateral flow may become inadequate after successful TCA.
Abstract:
The effect of increasing grades of collateral flow to the distal target vessel on the clinical and electrocardiographic manifestations of ischemia was evaluated in 118 patients undergoing transluminal coronary angioplasty (TCA). A qualitative scoring system for collateralization was defined as follows: 0--no visible collaterals; 1--visualization of collateral vessels only with no filling of the distal TCA vessel; 2--partial filling of the distal TCA vessel, and; 3--complete filling of the distal TCA vessel. All patients underwent computerized ST-segment monitoring using 3-channel Holter recorders. Criteria for an ischemic ST-segment response was 1.0 mm ST-segment deviation from ST baseline measured 60 msec after the J-point. Episodes of chest pain during and after the procedure were noted. Patients with collateral filling (collateral scores 2 and 3) of the distal TCA vessel had a significantly decreased incidence of angina and diagnostic ischemic ST-segment changes (42% and 15% respectively) as compared to patients without collateral filling (collateral scores 0 and 1) (83% and 74%) (p less than .001). Fifty-eight percent of patients without collateral filling had ischemic ST-segment responses on every balloon inflation as opposed to only 9% with collateral filling (p less than .0001). After TCA, the incidence of angina and ischemic ST-segment changes was similar in both groups (20% and 17% without collateral filling vs. 9% and 9%). We conclude that: 1. increasing qualitative collateralization protects against the development of myocardial ischemia during TCA, but; 2. the similar incidence of late episodes of ischemia after successful TCA suggests that collateral flow may no longer be adequate.