Acute Cardiac Care – Flow, Function and Beyond

What attracted me to cardiology as a student is the interaction between blood flow and pump function that is typical for the heart. The muscular ellipsoidal heart seems like wonderful machinery, one of nature's greatest creations, optimizing its performance through the complex interactions between muscular function, intracavity flow, coronary flow and its complex pathophysiology. This is also one of the reasons why many scientists and engineers are attracted to the challenge of solving theoretical and practical problems in the understanding and therapeutics of heart diseases.

In this issue, flow and function are touched upon in each and every paper. There have been many methods to measure epicardial coronary flow and myocardial perfusion. A review on that aspect is provided by Vijayalakshmi et al. [1] on methods to assess coronary flow in the cardiac catheterization laboratory. Methods focusing on scores deducted from angiography, as well as invasive hemodynamic measurements of blood flow are reviewed. Our ability to effectively and accurately measure flow, can certainly have a major impact on our diagnostic power and assist in the correct conclusions with respect to the prognosis and therapeutics of a particular problem. Flow of a viscous and thrombotic material such as blood, with all its multiple cellular constituents, interacting with the endothelial wall around it, is another fascinating interaction that integrates flow and function. Han et al. [2] show that the loss of endothelial function after PCI is a frequent event and propose a mechanism that may be related to impaired cleavage of a precursor protein to Brain Natriuretic Factor.

Stents, antiplatellet agents and coronary flow are tightly interrelated in modern cardiovascular medicine. A series of papers deal with drug eluting stents (DES) bare metal stents (BMS) and antiplatellet agents. Graft disease remains a major challenge to interventions today. Kaplan et al. [3] describe clinical results with DES implantation to ostial graft disease. DES achieves better clinical results than BMS but is still associated with a relatively high incidence of revascularization. The hypothesis that antiplatellet agents may have an additional role to DES in diabetic patients using abciximab is presented by De Luca et al. [4]. In a randomized, placebo controlled, trial no additional benefit of abciximab is demonstrated over DES. On another retrospective trial [5], abciximab effect on no-reflow phenomenon during primary angioplasty was evaluated, showing a major benefit for patients receiving abciximab. “Rescue abciximab” is therefore proposed as an effective option for the treatment of the no-reflow phenomenon. Obviously, selection bias and the retrospective nature of this paper require that these results are confirmed in further studies. Kornowski et al. [6] describe the odds ratio for developing restenosis with the good-old BMS. While DES have gained a significant role in certain lesion subsets, it becomes evident that BMS have a major role in interventional cardiology and optimization of the stent type to the patient and lesion subsets required additional studies.

Back to other aspects of flow and function, the first time use of the LIFEBRIDGE™ temporary circulatory assistance in high risk percutaneous revascularization case is described by Ferrari et al. [7]. This case illustrates the safe and easy use of a novel plug-and-play percutaneous circulatory assist device. The role of acute mechanical assistance for the heart during interventions is still under evaluation, but it is clear that short term assistance in acute pump failure may be the only way to rescue some individual patients. Preito et al. [8] have looked into the interesting disease of essential thrombocytosis in patients with acute coronary syndrome. Thrombotic and hemorrhagic complications in these patients may be seen but are rare. Kaminski et al. [9] describe oxidative stress after reperfusion therapy for acute myocardial infarction. Here again, the relationship between flow and function is highlighted. Restoration of flow does not necessarily lead to improved function and a paradoxical impairment of ventricular function may be related to oxidative myocardial damage. This issue is adjourned with Karavolias et al. [10] presenting an interesting image of RV infarction with unusual appearance.

In summary, while flow and function are key determinants of myocardial pathophysiology, many related aspects of cardiovascular disease are beautifully covered in this issue of the Journal. Acute cardiac care is typically the maintenance and restoration of the optimal balance between flow, function and beyond, using mechanical, pharmacological and biological means in the appropriate monitored setting.