Does myocardial perfusion scintigraphy predict improvement in symptoms and exercise capacity following successful elective percutaneous coronary intervention?

BACKGROUND: Elective percutaneous coronary intervention (PCI) without inducible ischaemia may not be beneficial. We investigated the prevalence of inducible hypoperfusion using myocardial perfusion scintigraphy (MPS) in patients undergoing PCI, and its ability to predict functional outcome. METHODS AND RESULTS: One hundred and twenty-three patients listed for elective PCI underwent MPS, using treadmill exercise where possible. Seventy-seven patients (63%) described chest pain in daily life. Seventy-four of 103 (72%) exercise ECG tests were positive. Ninety-one (74%) had inducible hypoperfusion on MPS (extensive in 25; 20%). Interventionalists were blinded to the scintigraphic results, and PCI was performed as planned. Six months later, Seattle Angina Questionnaire physical limitation score had improved from 66 to 76 (P < 0.0001), and peak treadmill workload from 7.2 +/- 2.3 to 9.0 +/- 2.7 METS (P < 0.0001). Sex, limiting chest pain on baseline exercise testing, and MPS summed difference score (SDS) were independent predictors of improvement. Patients with both limiting chest pain and SDS > or = 7 demonstrated an increase of 3.3 +/- 1.8 METS, compared with approximately 1.5 METS for other subgroups (P < 0.05). CONCLUSIONS: Many patients undergoing elective PCI in a UK centre have little or no evidence of inducible hypoperfusion. The combination of limiting chest pain during exercise testing and significant inducible hypoperfusion on MPS predicts a large increase in exercise capacity after PCI.

Clinical contribution of the collateral circulation to myocardial protection.

This section describes the clinical evidence for benefit from coronary collateral channels. There is data to suggest the presence of a protective effect in patients sustaining myocardial infarction regardless of whether they receive reperfusion therapy, and whether the collaterals were preformed. The role of pre-infarction angina in stimulating collateral development remains a contentious issue.

Time course and extent of collateral channel recruitment during coronary angioplasty.

OBJECTIVES: To assess the extent and timing of recruitment of collateral channels during coronary angioplasty in patients without spontaneous collaterals at diagnostic angiography. SETTING: The extent of collateral channel recruitment during coronary angioplasty is variable and its contribution to myocardial protection is not well established. The functional significance of collaterals recruited during balloon occlusion remains in question. PATIENTS: Collateral channels were assessed in 16 patients by contralateral injection at 30, 60 and 90 s into each of four 90 s inflations and by a 0.014 " Doppler guide wire distal to the lesion. RESULTS: Angiographic collateral recruitment was evident in 11 out of 16 patients (71%), but in only four (24%) by intracoronary Doppler. Grade I collaterals were present in seven patients, grade II in three and grade III in two. Collaterals were evident angiographically by 30 s in 10 out of 11 patients, with no progressive recruitment during subsequent inflations. In the four patients with Doppler evidence of collateral flow there were no differences in any flow velocity parameters with successive inflations. There was no difference in either maximum ST segment shift or time to 2 mm ST segment elevation between successive inflations. CONCLUSIONS: Collateral channel recruitment is variable between patients and appears maximal early in the first inflation. The lack of incremental recruitment of collaterals together with low or absent evidence of flow by Doppler wire suggests that these channels do not make a major contribution to myocardial protection in this setting.

Do clinical and angiographic parameters predict failure of medical therapy in patients suitable for coronary angioplasty?

AIMS: Recent studies have suggested that patients with coronary disease suitable for angioplasty have an equally good outcome with medical therapy if clinically stable. Complex lesion morphology may predict acute events without intervention and stenosis severity influences the degree of collateralisation. This study was designed to assess the influence of these factors on clinical outcome. METHODS AND RESULTS: A retrospective review of patients suitable for angioplasty who were randomised to initial medical therapy as part of a multicentre study. Angiograms were reviewed for lesion characteristics, TIMI flow grade, and degree of collateralisation. Angiograms were available on 79 patients (13 female, 66 male). Mean age was 54.8 years (range 43-68) in the group crossing-over to revascularisation, and 58.4 (range 37-78) in the group who did not (P=ns). Seventeen patients crossed-over (two to CABG, 15 to PTCA) at 5.4 months (range 0-10) after initial angiography. Disease progression had occurred in 10/17 patients (58.8%), three of whom developed a new occlusion. Collateralisation was more likely in smokers, independent of lesion severity (P<0.05). Time to cross-over was not influenced by progression of disease. Crossing-over was not affected by age, diabetic status, cholesterol level, vessel involved, lesion severity, TIMI flow, lesion morphology, collateralisation, or the number of vessels diseased, but was more likely in females (P<0.05). CONCLUSION: This group of patients generally does well with medical therapy. Whilst the numbers are relatively small, there does not appear to be any reliable prospective marker, including the presence of spontaneous collateral channels on diagnostic angiography, to indicate which patients will fail medical therapy and require revascularisation.

Percutaneous coronary intervention of a circumflex chronic total occlusion using an epicardial collateral retrograde approach.

Antegrade disobliteration of a chronic total coronary occlusion (CTO) may be technically difficult in spite of the use of customized equipment. Retrograde approaches via intramyocardial septal or bypass grafts have been described. We report a successful Percutaneous intervention of a proximal circumflex CTO using a retrograde approach via an epicardial collateral.