Coronary Sinus Techniques in Interventional Cardiology

Coronary sinus interventions seem to be today's concept of myocardial protection in ischemic syndromes. Basically we discriminate between synchronized retroperfusion (SRP), PICSO, and synchronized suction and retroinfUsion (SSR). There has been a long debate about the advantages of any of these methods which was misleading, manipulating and disasterous for all concepts. Coronary sinus interventions will come fully into effect when we clearly can define the patients' characteristics, inclusion/exclusion criteria and the proper indication for each of the methods.

SRP is applied by a catheter positioned into the coronary sinus to retroperfuse arterial blood into the venous system. The benefits of the method have been shown in several ischemic syndromes. However, it seems questionable whether blood can be forced upstream as far as to reach the ischemic area in the relatively large and interconnected venous meshwork. Incomplete myocardial protection by synchronized coronary venous retroperfusion during ischemia might result from nonselective retroinfusion and solely passive drainage. Therefore, in a modified concept (SSR), the catheter is more selectively advanced into the venous circulation and an active suction system is added to the retroinfusion device. In this way, the obstacles of SRP seem to be mainly overcome, and better preservation of regional function could be proven experimentally.3

PICSO follows a different concept of using venous blood to maintain cell viability during ischemic syndromes. The rationale of PICSO holds that the beneficial effects are mainly due to forced redistribution of venous blood flow into the coronary beds. In contrast to retroperfusion and its primary effect of oxygen delivery, the effect of PICSO appears to result from redistribution and washout of toxic metabolites.6 For a long time surgeons have been aware of the effect of oxygen toxicity and reperfusion injury and therefore it seems reasonable to start reperfusion with a modified reperfusate making use of the enormous metabolic and buffer potential of venous blood until ultimate reperfusion from the arterial side can be established, i.e., thombolysis in myocardial infarct. The concept of a substantial contribution of PICSO to myocardial metabolite washout resulting in improved tissue salvage and maintained function during acute ischemia is consistent with observations of Murry14 and Neely.15 These authors showed a relationship between cell integrity, viability, functional recovery, and catabolic accumulation during ischemia and reperfusion. Since numerous experimental studies showed that PICSO reduces infarct size, this method should be primarily used during myocardial infarction and unstable angina pectoris and to avoid reperfusion injury (cf. Table 1.1).

Bearing in mind the limitations of all these methods of coronary sinus interventions— i.e., the anatomy and pathophysiology of the venous vasculature and drainage pathways, feasibility, potential hazards, different concepts and indications—coronary sinus techniques can be applied beneficially during cardiac surgery as well as in the catheter lab and, even more important, during myocardial infarction (see Table 1.2).

References

1. Beatt KJ, Serruys PW, Feyter P et al. Hemodynamic observations during percutaneous transluminal coronary in the presence of synchronized diastolic coronpary sinus retroperfusion. Br Heart J 1988; 59:159-67.

2. Beck CS. Revascularization of the heart. Surgery 1949; 26:82-88.

3. Boekstegers P, Peter W, von Degenfeld G et al: Preservation of regional myocardial function and myocardial oxygen tension during acute ischemia in pigs: Comparison of selective synchronized suction and retroinfusion of coronary veins to synchronized coronary venous retroperfusion. JACC 1994; 23:459-469.

4. Buckberg GD. Antegrade/retrograde blood cardioplegia to ensure cardioplegic distribution: Operative techniques and objectives. J Cardiac Surg 1989; 4:216-238.

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