Chronic stable angina revascularization adjunctive pharmacotherapy for percutaneous coronary intervention


 * Associate Editor(s)-In-Chief: Lakshmi Gopalakrishnan, M.B.B.S.

Vasospasm during PCI:

 * Nitroglycerine a coronary vasodilator, increases the sub-endocardial perfusion secondary to enhancement of the coronary collateral flow. Hence, prophylactic intracoronary nitroglycerine may be used not only to reduce the risk of vasospasm and vasospastic reactions during PCI but also helps to assess the true vessel diameter.

No reflow phenomenon during PCI:

 * At various doses, intracoronary dipyridamole or adenosine may be used to treat no reflow phenomenon, which is characterized by inadequate tissue level flow in spite of a maximally dilated epicardial vessel.


 * Selective intracoronary administration of a direct nitric oxide donor such as nitroprusside prior to PCI has also shown to be safe and effective in the treatment of no reflow phenomenon associated with PCI, and has shown to improve myocardial perfusion.


 * A combination of adenosine and nitroprusside has shown to provide better improvement in the coronary flow in comparison to the use of intracoronary adenosine alone.

Aspirin:

 * In the M-HEART II trial (1995), 752 patients were randomized to receive aspirin (a nonselective thromboxane A2 synthesis inhibitor), sulotroban (a selective thromboxane A2 receptor blocker) or a placebo that was started 6 hours before and continued for 6 months after PCI, to evaluate the effects antiplatelet agents on the late clinical events and restenosis after PCI. At 6-month follow-up, aspirin was reported to significantly improve the clinical outcome in comparison to placebo (p=0.46) and sulotroban (p=0.006). The incidence of myocardial infarction was also significantly reduced with the administration of antithromboxane therapy from 5.7% in the placebo group to 1.2% in the aspirin group (p=0.030). However, the rate of restenosis did not significantly differ among the three groups: 39% in the aspirin group, 43% in the placebo group and 53% in the sulotroban group. Thus, the study concluded anti-thromboxane therapy is beneficial to reduce the ischemic complications related to PCI; in particular, aspirin if continued at least for 6 months after coronary angioplasty significantly reduced the incidence of MI and improved the overall clinical outcome.


 * In the meta-analysis (2002) from Antiplatelet Trialists’ Collaboration, 287 randomized trials involving 135000 patients were randomized to receive either antiplatelet therapy or control and 77000 were randomized to different antiplatelet regimens, to determine the effects of antiplatelet therapy among patients at high risk of occlusive vascular events. The absolute reduction in the risk of having a serious vascular event was 36 (SE 5) per 1000 treated for two years among patients with previous myocardial infarction; 36 (SE 6) per 1000 treated for two years among those with previous stroke; 9 (SE 3) per 1000 treated for three weeks among those with acute stroke; and 22 (SE 3) per 1000 treated for two years among other high risk patients with separately significant results for those with stable angina (p=0.0005) and atrial fibrillation (p=0.01). In each of these high risk categories, the absolute benefits of aspirin substantially outweighed the absolute risks of major extracranial bleeding. Among patients at high risk of immediate coronary occlusion, addition of a intravenous glycoprotein IIb/IIIa inhibitor to aspirin for a short period, prevented a further 20 (SE 4) vascular events per 1000 (p=less than 0.0001) but caused 23 major extracranial bleeds per 1000. Thus, the study concluded aspirin at a dose of 75-150 mg/day, has shown reduced mortality and the incidence of vascular events among all high-risk patients including patients with previous or acute MI, unstable or stable angina.