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PubMed1984

[Transitory appearance of collateral circulation during coronary spasm].

The authors report the case of a patient with coronary spasm characterised on exercise stress testing by an initial depression of the ST segment followed by ST elevation at the 3rd minute of recovery. Coronary angiography showed an important, transient collateral system arising from the left coronary artery, probably minimising the effects of complete occlusion of a dominant right coronary artery. The authors discuss effort-induced spasm and collateral circulation.

Collateral Circulation↗
PubMed2004

Reciprocal relationship between left ventricular filling pressure and the recruitable human coronary collateral circulation.

AIMS: The aim of our study in patients with coronary artery disease (CAD) and present, or absent, myocardial ischaemia during coronary occlusion was to test whether (i) left ventricular (LV) filling pressure is influenced by the collateral circulation and, on the other hand, that (ii) its resistance to flow is directly associated with LV filling pressure. METHODS AND RESULTS: In 50 patients with CAD, the following parameters were obtained before and during a 60 s balloon occlusion: LV, aortic (Pao) and coronary pressure (Poccl), flow velocity (Voccl), central venous pressure (CVP), and coronary flow velocity after coronary angioplasty (V(Ø-occl)). The following variables were determined and analysed at 10 s intervals during occlusion, and at 60 s of occlusion: LV end-diastolic pressure (LVEDP), velocity-derived (CFIv) and pressure-derived collateral flow index (CFIp), coronary collateral (Rcoll), and peripheral resistance index to flow (Rperiph). Patients with ECG signs of ischaemia during coronary occlusion (insufficient collaterals, n = 33) had higher values of LVEDP over the entire course of occlusion than those without ECG signs of ischaemia during occlusion (sufficient collaterals, n = 17). Despite no ischaemia in the latter, there was an increase in LVEDP from 20 to 60 s of occlusion. In patients with insufficient collaterals, CFIv decreased and CFIp increased during occlusion. Beyond an occlusive LVEDP > 27 mmHg, Rcoll and Rperiph increased as a function of LVEDP. CONCLUSION: Recruitable collaterals are reciprocally tied to LV filling pressure during occlusion. If poorly developed, they affect it via myocardial ischaemia; if well grown, LV filling pressure still increases gradually during occlusion despite the absence of ischaemia indicating transmission of collateral perfusion pressure to the LV. With low, but not high, collateral flow, resistance to collateral as well as coronary peripheral flow is related to LV filling pressure in the high range.

Aged↗
PubMed1997

Impact of severity of coronary artery stenosis and the collateral circulation on the functional outcome of dyssynergic myocardium after revascularization in patients with healed myocardial infarction and chronic left ventricular dysfunction.

The aim of this study was to assess the influence of the severity of coronary artery stenosis and the grade of collateral circulation on myocardial viability in patients with chronic left ventricular (LV) dysfunction undergoing coronary artery bypass grafting. Forty patients (age 59 +/- 8 years) with old myocardial infarction were studied by dobutamine stress echocardiography (DSE) before coronary artery bypass grafting. LV function was assessed using a 16-segment, 5-grade score model. Viability and functional recovery were respectively defined as a reduction in wall motion score > or = 1 at low-dose DSE and at follow-up echocardiograms obtained 3 months after surgery. There were 56 stenotic coronary arteries subtending severely dyssynergic myocardial segments, of which 38 were occluded. Among 186 severely dyssynergic segments, functional recovery occurred in 42 (23%). There was no significant difference between myocordial regions with patent or occluded coronary arteries with respect to prevalence of viability or functional recovery and percentage of viable or recovered segments relative to the total number of dyssynergic segments. In patients with total occlusion, these parameters were not different between regions with different collateral grades. Sensitivity, specificity, and accuracy of low-dose DSE for prediction of regional functional recovery were 71%, 90%, and 86%, respectively. It is concluded that in patients with chronic LV dysfunction, the presence of total occlusion of coronary arteries supplying severely dyssynergic regions does not imply a lower prevalence or extent of functional recovery after revascularization, regardless of the grade of angiographically visualized collaterals. Low-dose DSE can identify myocardial regions with a high probability of functional improvement after revascularization regardless of the severity of underlying coronary stenosis or collateralization of the involved coronary vessel.

Collateral Circulation↗
PubMed1989

Acceleration of cell necrosis following reperfusion after ischemia in the pig heart without collateral circulation.

A study of whether reperfusion accelerates cell death was performed in 35 pig hearts without collateral circulation. In 15 animals, the distal one-third of the left anterior descending coronary artery was occluded for 1 hour followed by 1-, 3-, or 7-hour reperfusion in 5 animals each. As controls, 5 hearts each were examined after 1, 2, 4 and 8 hours of occlusion of the artery without reperfusion. Heart rate and aortic pressure before and during occlusion and reperfusion did not change in any group. The subepicardial and subendocardial regional blood flow decreased to almost zero in all hearts after occlusion (85 +/- 1 to 2 +/- 2) but recovered during reperfusion (65 +/- 15 ml/100 g/min). Specimens were histologically examined by an enzyme method using nitrotetrazolium blue, an immunohistochemical method using myoglobin antibody, by staining with hematoxylin-eosin and Masson's trichrome. In the control hearts, clear demarcation of the infarct area was observed 4 hours after occlusion. However, in the reperfusion group, clear demarcation of the infarct was seen after 1-hour reperfusion, namely, 2 hours after the onset of infarct. Demarcation was seen not only in the tissue with contraction band necrosis, but also in the tissue with coagulation necrosis. Therefore, it is concluded that reperfusion accelerates cell death due to both contraction band necrosis and coagulation necrosis.

Animals↗
PubMed1980

Importance of collateral circulation of bowel in urologic surgery.

As urologic surgery becomes more extensive planned or inadvertent compromise of the vascular supply of the bowel becomes more likely. Familiarity with the normal anatomy of the vascular supply of the large and small intestines must, therefore, be part of every urologist's fund of knowledge. With an appreciation of the critical areas of collateral circulation conclusions can be drawn as to which arteries can and cannot be ligated safely. Intraoperative Doppler flow studies may help the surgeon to evaluate whether collateral supply is adequate to maintain bowel viability. In certain marginal situations hydration and postoperative treatment with antibiotics may be helpful.

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PubMedDate not supplied

Collateral circulation following repeated distal embolization of the hepatic artery in pigs.

The distal hepatic arteries of eight pigs were embolized weekly with nondegradable microparticles. Hepatic angiograms were obtained before and after each embolization. One week after the last embolization Microfil was injected into the arterial and portal vascular beds of the liver prior to sacrifice. This study reveals that extensive collateral circulation develops after both primary and repeat embolization. After a third embolization in four of the pigs, the hepatic arterial circulation was almost totally abolished in two pigs with resulting extensive liver necrosis. An intact portal circulation is not sufficient to prevent infarction in dearterialized liver parenchyma.

Animals↗