Journal and News Scan

This retrospective review of outcomes after reconstruction of the intervalvular fibrous trigone combined with aortic and mitral valve replacement  tracked patients who were operated upon for either severe endocarditis (n=26) or severe calcification (n=14) involving the trigone.  The David Technique for reconstruction was used, and the operative mortality for these complex operations was 15% and 7%, respectively.  Despite high operative risk and complexity, the authors from Madrid show that this operation can be performed with respectable morbidity and mortality rates.

Comparing 714 on pump and 714 off pump CABG patients, the investigators investigated the incidence of Acute Kidney Injury (AKI) and whether cardiopulmonary bypass time and or duration were independent contributors to AKI.  The investigators concluded that there are no differences in the incidence of AKI during  CABG surgery employing CPB. Use of off-pump bypass for patients with pre existing AKI may avoid further injury.

As the debate rages on about which technique is superior, several concerns come to mind.

1. When comparing on pump to off pump most studies do not look at the perfusion circuit as a whole to determine prime volume, which contributes to excessive hemodilution and is associated with AKI and increased transfusions.

2. Most studies do not evaluate the use of intra-aortic filtration for the capture of atheroma during aortic cross clamp application and removal. These potential embolic events are known contributors to renal, neurologic, and other sequelae.

3. Most studies do not include data such as continuous cardiac output measurements or cerebral oximetry measurements during off pump CABG. Cardiac anesthesiologists are excellent clinicians that can give the surgeon whatever systemic pressure is desired, while in reality, perfusion may be severely compromised.

4. During on pump surgery, would it be beneficial to perform continuous veno-veno hemofiltration with bicarb based solutions to clear pro inflammatory mediators and maintain physiologic homeostasis. This is more easily achieved in the on pump group and it perhaps a worthwhile addition to the CPB circuit to investigate in regards to reducing post op AKI.

This study evaluated potential safety concerns of using NSAIDS in combination with antithrombotic agents 30 days or more after MI.  The population studied was comprised of nearly 62,000 Danish patients.  Use of NSAIDs at any time doubled the risk of a bleeding episode and increased the risk of a major cardiovascular event by 40%.  The NSAIDs risks were present even after short-term NSAIDS use. 

Resently confronted with the problem of plasma leakage out of the gas exhaust port of the oxygenator, necessesatatting changing of the oxygenator several times in 48 hours. We noted that the the plasma in the discarded oxygenator that had seperated was milky white in color and we checked for hyperlipidemia which was affirmed. In addition, propofol was being used and the patient had elevated glucose levels. An insulin drip was started and the propofol replaced with versed. The subsequent oxygenator survived 6 hours and hte next over 24 hours indicating improvment. Measured lipid levels wer also lower. 

Believeing that the root couse was the hyperlipidemia but not having confirmation of this, I contacted an engineering friend that works with these types of hollow fibers. He subsequently forwarded me this article.

The investigators, under experimental conditions, created plasma leakage in the hollowfiber oxygenators and conclude that the absorbtion of phospholipids leads to the formation of a hydrophilic layer over the surface of the membrane which is hydrophobic leading to plasma leakage.