Related Experiment Videos
Autologous blood perfusion for myocardial protection during coronary angioplasty: a feasibility study
Insights
Oxygenated autologous blood perfusion during coronary angioplasty mitigates myocardial ischemia. This safe and effective technique reduces pain and ST segment elevation, potentially expanding angioplasty for high-risk patients.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Biomedical Engineering
Background:
- Coronary angioplasty involves balloon inflation, causing temporary arterial blockage and myocardial ischemia.
- Delivering oxygenated blood to the heart muscle during this period may reduce ischemic damage.
Purpose of the Study:
- To assess the feasibility and safety of infusing oxygenated autologous blood during coronary angioplasty.
- To evaluate the efficacy of this technique in mitigating myocardial ischemia.
Main Methods:
- In vitro testing of blood infusion through a dilatation catheter at various flow rates (up to 120 ml/min).
- Evaluation of hemolysis, potassium release, and blood cell integrity in vitro.
- A randomized, crossover clinical trial in 15 patients undergoing coronary angioplasty, comparing blood perfusion at 60 ml/min with standard inflation.
Main Results:
- In vitro: Hemolysis and potassium release increased exponentially above 60 ml/min. Red blood cell fragments were observed at higher rates.
- In vitro: Platelet, leukocyte counts, beta-thromboglobulin, and muramidase remained stable.
- Clinical trial: Blood perfusion at 60 ml/min resulted in significantly lower pain scores and reduced ST segment elevation compared to control inflations.
- Clinical trial: Plasma hemoglobin, lactate dehydrogenase, and potassium levels remained stable during perfusion.
Conclusions:
- Oxygenated autologous blood perfusion at 60 ml/min is a safe and feasible method to protect the myocardium during coronary angioplasty.
- This technique significantly reduces patient discomfort and indicators of myocardial ischemia.
- The method may allow for longer inflation times and broaden the applicability of coronary angioplasty to higher-risk individuals.
Abstract:
During coronary angioplasty, inflation of the balloon within the coronary artery produces transient arterial occlusion and frequently results in myocardial ischemia. Delivery of oxygenated autologous blood to the myocardium at risk during inflation may help mitigate this ischemia. Accordingly, we investigated the feasibility and safety of infusing blood through the central lumen of a dilatation catheter around the guidewire using both a model in vitro and clinical trials. In the tests in vitro, fresh blood was infused at flow rates up to 120 ml/min. Hemolysis was minimal at flow rates of 60 ml/min or less (less than or equal to 0.92 +/- 0.18%), but increased exponentially at higher rates (13.64 +/- 2.37% at 120 ml/min, p less than .002). A similar pattern was observed for potassium release. Platelet and leukocyte counts did not vary significantly, and beta-thromboglobulin and muramidase remained at control levels. Although mean erythrocyte volume did not change, erythrocyte histograms and light microscopy demonstrated a subpopulation of red cell fragments averaging 25 to 40 fl in size at higher rates. A randomized, crossover clinical trial was next performed by delivery of blood perfusion at 60 ml/min to 15 patients undergoing coronary angioplasty. Levels of plasma hemoglobin, beta-thromboglobulin, lactate dehydrogenase, and potassium remained constant before and after the perfusion and the control inflations. The maximum pain score was significantly lower with the perfusion inflation (4.1 +/- 0.8 vs 6.0 +/- 0.9, p less than .003). Relative to baseline, the maximum ST segment elevation during the perfusion inflation (0.5 +/- 0.3 mm) was nearly one-fourth that during the control inflation (1.9 +/- 0.6 mm, p less than .02). Thus, myocardial protection with oxygenated autologous blood perfusion at rates of 60 ml/min appears to be a safe and effective technique that may permit increased inflation time and extend the range of coronary angioplasty to include individuals at high risk for the procedure.