Aronow, Wilbert S.

Coronary artery spasm (CAS) is a dynamic vasomotor disorder characterized by transient, intense constriction of epicardial coronary arteries, leading to myocardial ischemia in patients with and without obstructive coronary artery disease. CAS plays a central role in vasospastic angina, ischemia with nonobstructive coronary arteries and myocardial infarction with nonobstructive coronary arteries, malignant arrhythmias, and sudden cardiac death. Its pathophysiology is multifactorial, involving endothelial dysfunction, vascular smooth muscle hyperreactivity, inflammation, oxidative stress, autonomic imbalance, and genetic susceptibility, with notable ethnic and sex-related differences. Diagnosis relies on integration of clinical features, electrocardiographic changes, and invasive coronary provocation testing using acetylcholine or ergonovine, supported by advanced imaging and functional assessment when microvascular involvement is suspected. Management is centered on calcium channel blockers and nitrates, aggressive risk factor modification, particularly smoking cessation, and individualized strategies for refractory or high-risk patients. Improved recognition and standardized diagnostic pathways are essential to optimize outcomes and reduce life-threatening complications associated with CAS.

Shock is a life-threatening state of circulatory failure characterized by inadequate tissue oxygen delivery and cellular hypoxia. Lactate has emerged as a central biomarker in the diagnosis, risk stratification, and management of shock, yet its interpretation is complex and context dependent. Although traditionally viewed as a marker of anaerobic metabolism and tissue hypoperfusion, hyperlactatemia in distributive shock, particularly sepsis, frequently reflects multifactorial mechanisms, including increased aerobic glycolysis, adrenergic stimulation, mitochondrial dysfunction, and impaired hepatic clearance. This review examines the pathophysiology and classification of shock, the biochemical basis of lactate production and clearance, and the prognostic significance of both static lactate levels and lactate kinetics. We synthesize evidence supporting lactate as a robust prognostic marker while highlighting limitations of lactate-targeted resuscitation strategies. Emerging data favor multimodal approaches integrating lactate trends with complementary perfusion markers such as capillary refill time and central venous oxygen saturation. Lactate should be interpreted as one component of a comprehensive physiological assessment rather than an isolated therapeutic target.