Slow Coronary Flow: Pathophysiology, Clinical Implications, and Therapeutic Management

Abstract

Coronary slow flow (CSF) is an angiographic phenomenon with specific epidemiologic characteristics, associated clinical presentation, and prognosis. Although patients with CSF are diagnosed as having “normal coronary arteries,” it seems appropriate to consider CSF as a distinct disease entity requiring specific treatment. The patient with CSF is usually male, smoker, obese, with a constellation of risk factors suggestive of metabolic syndrome. Unstable angina is the most common clinical presentation, with recurrent episodes of chest pain at rest associated with electrocardiographic changes often requiring readmission and reevaluation. Regarding definition and diagnosis, interventionists should first exclude possible “secondary” causes of CSF, use objective means for definition and then differentiate from other similar conditions such as microvascular angina. Although the phenomenon is generally benign, patients with CSF are severely symptomatic with recurrent episodes of chest pain and poor quality of life. Furthermore, acute presentation of the phenomenon is commonly life-threatening with ventricular tachyarrhythmias, conduction abnormalities, or cardiogenic shock. Acute treatment of CSF includes, but is not restricted to, intracoronary infusion of dipyridamole, adenosine, or atropine. Chronic management of patients with CSF encompasses dipyridamole, diltiazem, nebivolol, telmisartan, and/or atorvastatin associated with amelioration of angina symptoms, improved quality of life, and good prognosis.

Slow Coronary Blood Flow: Pathogenesis and Clinical Implications

“…56 Also in the acute presentation, Chalikias et al have recently published the use of intracoronary atropine, with an anticholinergic effect, as an appropriate agent to quick reversal of CSF. 57 In conclusion, different agents and therapies have been studied for CSF and previous reports have shown the benefit of using dipyridamole by decreasing the microvascular tone, and others have proved the effects of angiotensin-converting enzyme inhibitors by modulating coronary microvascular tone but until now there is no clear treatment for this phenomenon. 58,59 Evidence for the management of these patients is weak as there are no large randomised control trials but CCBs are the most promising treatment.…”

“…[ 56 ] Also in the acute presentation, Chalikias et al have recently published the use of intracoronary atropine, with an anticholinergic effect, as an appropriate agent to quick reversal of CSF. [ 57 ]…”

Immediate versus Deferred Stenting for Patients Undergoing Primary Percutaneous Coronary Intervention

“…In patients with TIMI flow of 0-1 in the infarct-related artery on arrival to the emergency department [ED], the lesion was wired, thrombectomy and balloon dilatation were done if indicated [with a balloon diameter substantially smaller than the reference size of the vessel] to restore and stabilize TIMI 2-3 flow using as little manipulation of the lesion as possible. The TIMI flow was categorized from 0 to 3, as described by Chalikias and Tziakas [18] .…”

Defining Coronary Slow Flow

“…In this issue of Angiology , Chalikias and Tziakis 17 review the specific epidemiologic characteristics, clinical features, and prognosis of CSFP. However, whether CSFP should be considered a specific coronary syndrome or a stage in the development of CMD remains undefined.…”

“…This is especially true in the earlier stage of atherosclerotic disease when positive coronary remodeling allows apparently preserved lumen size despite the presence of wall plaques. 22 As the authors point out, 17 intravascular ultrasound imaging suggests that CSFP may be a form of diffuse atherosclerosis involving both the microvascular system and epicardial coronary arteries. 23,24 Indeed, there are close relationships between structural and functional changes of epicardial and microvascular circulation, which may be considered expression of the same atherosclerotic process and may strongly influence each other.…”