Endothelial function can be preserved during cryo-storage of human saphenous vein.

Endothelial functional integrity was quantified in human saphenous vein by measurement of stimulated (vortex-mixing) rates of prostacyclin production. Prostacyclin production was not inhibited by dimethylsulphoxide (DMSO), glycerol or sucrose at concentrations normally used for cryopreservation. Rapid freezing followed by storage for 3-4 weeks and thawing of veins pretreated with 15% (v/v) dimethylsulphoxide significantly impaired prostacyclin production. In contrast, slow freezing and thawing in the presence, but not the absence, of DMSO led to complete retention of prostacyclin production. We conclude that endothelial function can be preserved during cryostorage.

Nature and pressure dependence of damage induced by distension of human saphenous vein coronary artery bypass grafts.

Surgical preparation of human saphenous vein for coronary artery bypass grafting involving distension and storage in iso-osmotic sodium chloride solution reduced tissue adenosine triphosphate (ATP) (mean(SEM] concentration from 280(20) nmol.g-1 wet wt (n = 25) to 140(30) nmol.g-1 wet wt (n = 12) and the adenosine triphosphate to adenosine diphosphate (ATP:ADP) concentration ratio from 2.4(0.1) to 1.2(0.2). Since removal of endothelium from freshly isolated vein did not affect ATP concentration or ATP:ADP ratio, these changes quantified medial damage. Distension of the vein at a pressure of 150 mmHg caused no change in ATP concentration or ATP:ADP ratio, but these values were reduced progressively by distension at 300 mmHg and 600 mmHg. Damage was not reversed but was exacerbated by subsequent incubation of the distended vein in blood. Distension of the vein at 600 mmHg caused release of tissue lactate dehydrogenase. The data show that acute medial damage can result from distension of the vein but that this does not occur at pressure equivalent to normal arterial pressure. Distension induced medial damage is unlikely to be rapidly reversible.

Chronic proximal aortic dissection presenting as tamponade after 16 years.

A patient presented with tamponade and haemopericardium 16 years after experiencing sudden severe chest pain associated with enlargement of the proximal aorta. Investigations revealed a proximal aortic dissection (DeBakey type II) with extensive laminar and partially calcified thrombus within its false lumen and a large pericardial effusion, which together resulted in a cardiothoracic ratio of 100%. Long term survival after medical treatment of proximal aortic dissection, with such late progression to tamponade, has not been reported before.

Intravenous adenosine in the treatment of supraventricular tachycardia: a dose-ranging study and interaction with dipyridamole.

Increasing doses of adenosine were given by rapid intravenous bolus to seven patients with spontaneous supraventricular tachycardia. Adenosine restored sinus rhythm in 10 of 14 episodes of narrow complex tachycardia. In those patients in whom adenosine produced only transient ventricular slowing the underlying rhythm was atrial flutter. Transient dyspnoea occurred in all patients. In two patients taking dipyridamole the mean dose of adenosine which produced an electrophysiologic effect (restoration of sinus rhythm or ventricular slowing to under 100 beats min-1) was 1.0 +/- 0.52 mg, whereas in other patients the mean dose was 8.8 +/- 2.6 mg, suggesting potentiation of the action of adenosine by dipyridamole.

A comparative study of median sternotomy and standard thoracotomy wound skin closure methods.

Complications from skin closure after median sternotomy or standard thoracotomy incision, although uncommon, may be the source of undesireable morbidity and even death. A prospective randomized study of 3 different methods of wound skin closure has been carried out in 205 patients undergoing cardiothoracic surgery. These methods were: 1. continuous nylon vertical mattress suture; 2. continuous subcuticular absorbable (Dexon) suture; 3. adhesive sutureless skin closure (Op-Site). All wounds were examined by independent observers at 5, 10 and 45 days after operation, and the findings were graded from 0 to 4. At 5 days, assessments were made of inflammation, edema, discharge and infection. At 10 days, attention was paid to the state of wound healing, and at 45 days to the final cosmetic appearance. The use of continuous subcuticular Dexon suture resulted in less discharge than Op-site (p less than 0.001) and less swelling or redness than nylon (p less than 0.001). Assessment of the final cosmetic appearance of the wound 6 weeks following surgery showed subcuticular Dexon to be superior to either nylon (p less than 0.01) or Op-site (p less than 0.01).