Left Ventricular Volume Reduction: New Dawn or False Horizon? Basic Science and Clinical Doubts

Abstract Left ventricular volume reduction surgery (LVVR) for end-stage dilated cardiomyopa-thy is a surgical option used selectively but with unclear long-term results. Increasing numbers of reports are appearing in the literature. These should be pooled into an international registry through collaborative efforts that allow for more effective analysis. Furthermore, high priority must be given to identify subgroups of patients who will potentially gain most benefit from LVVR. Basic science may add invaluable data and in this article we describe how intraoperative myocardial biopsies from patients with idiopathic dilated cardiomyopathy were utilized to isolate myocytes in an effort to determine differential physiological characteristics at the cellular level. The result showed various degrees of contractile anomalies in response to electrical stimulation associated with defective calcium handling as reflected by measurements of calcium transients. It is hoped that this approach may be extended to preoperative catheter biopsy to gain information that will facilitate patient selection to avoid unnecessary surgical failures.     

Evaluation of carotid endarterectomy with sequential MR perfusion imaging: a preliminary report.

BACKGROUND AND PURPOSECurrent indications for carotid endarterectomy are determined by balancing the relative risks of surgery with the benefits of reduced risk of subsequent stroke. Our purpose was to use MR perfusion imaging to assess patients being considered for carotid endarterectomy and to monitor sequential changes in MR perfusion characteristics after surgery. In particular, we wished to determine whether this technique could be used to detect changes that might be related to post-carotid endarterectomy hyperemia.METHODSWe used a single-section gradient-recalled echo sequence to investigate 14 patients being examined before possible surgery for carotid artery disease. In the 12 patients in whom carotid endarterectomy was performed, sequential studies were performed 3 to 5 days after surgery and at 3 months. Analysis of bolus-arrival-time (BAT) images was performed.RESULTSSignificant delays in preoperative BAT images of 0.89 seconds (range, 0.05 to 3.22 seconds) were apparent between hemispheres. Excluding the two patients with contralateral internal carotid artery (ICA) occlusion, early arrival, possibly indicating postoperative hyperemia, was seen in five patients immediately after carotid endarterectomy but resolved within 3 to 5 months after surgery.CONCLUSIONMR perfusion imaging shows differences in BAT between hemispheres in patients with ICA stenosis. Changes in perfusion characteristics after carotid endarterectomy are complex, and early BAT on the operative side can occur soon after endarterectomy in over half those patients without an occluded contralateral vessel. The significance of these findings with regard to patient outcome and risk of postoperative hyperemia requires further investigation.     

Spinal cord blood flow in dogs : 2. The effect of the blood gases

The effect of CO₂ on the spinal cord blood flow was investigated in nine dogs. The flow was closely correlated with the paCO₂ and at about 85 mmHg was double the normocarbic flow. The effect of pO₂ was studied in a further nine dogs. Hypoxia markedly increased the flow which was maximal at paO₂ 30-40 mmHg. The vasoconstrictor effect of hypocarbia was absent or decreased in hypoxia. The response of the cord vessels to the blood gases was very similar to that of the brain.     

Alkaline phosphatases. Newer concepts in isoenzymes and clinical applications

ALP is a profoundly ubiquitous enzyme that originates in many, if not all, mammalian tissues. The development of a simple ISEF technique has allowed reflection of at least 12 cellular components. Improvements in technique may add further zones of information. The aura of darkness surrounding ALP is being slowly dissipated.