PubMed Health⌕ Search

Biomedical subjects

K Verkkala

Publications and source records attributed to K Verkkala.

At least 37 records · Page 2Linked to original sources
PubMed1995

Prostaglandin E1 or prostacyclin in Euro-Collins solution fails to improve lung preservation.

BACKGROUND: In search of the ideal composition of the flush solution for pulmonary preservation, we studied the effects of prostaglandin E1 (PGE1) and prostacyclin as an additive to Euro-Collins solution (ECS) on pulmonary hemodynamics and gas exchange in a porcine single lung transplantation model using extracorporeal circulation and right heart bypass. METHODS: Twenty-two pigs served as donors. The animals were randomized to receive either modified ECS alone (control group, n = 8), ECS with 100 micrograms/L of PGE1 (PGE1 group, n = 6), or ECS with 200 micrograms/L of prostacyclin (prostacyclin group, n = 8). Left lung transplantation was performed in 22 recipients after approximately 4 hours of cold ischemia. RESULTS: Carbon dioxide elimination was significantly depressed in the two prostaglandin groups, and the use of PGE1 was associated with a significant decrease in arterial oxygen tension compared with the control group. Both drugs were inefficient in alleviating the increase in pulmonary vascular resistance after transplantation. CONCLUSION: The use of prostaglandins as constituents of the flush solution was not followed by any improvement of early graft function after cold ischemia.

Alprostadil↗
PubMed1994

Continuous positive airway pressure by mask in patients after coronary surgery.

Thirty patients who underwent coronary artery bypass grafting were randomized to receive 30% oxygen by mask either with an ambient airway pressure or with 7.4 mmHg (1 kPa) continuous positive airway pressure (CPAP) for 8 h after extubation. Arterial blood oxygen tension (PaO2) decreased remarkably in the control group after extubation (from 19.2 +/- 5.3 kPa to 12.4 +/- 2.7 kPa) but less in the CPAP group (from 16.4 +/- 3.3 kPa to 14.0 +/- 2.1 kPa). On the second postoperative morning PaO2 was equally low in both groups (control: 8.4 +/- 1.5 kPa, CPAP: 8.9 +/- 1.9 kPa). Atelectatic areas were seen with similar frequency in both groups, 17% (whole material) on the first and 50% on the second postoperative morning. Atelectasis was more common in patients with internal thoracic artery grafting and/or pleural drainage. In conclusion, CPAP therapy was well tolerated, and minimized the decrease in PaO2 after extubation, but could not prevent the poor oxygenation or the late development of atelectatic areas on the second postoperative day.

Adult↗
PubMed1994

Periprosthetic leakage after aortic valve replacement.

During the period 1968-1985, aortic valve replacement was performed in 871 patients, 617 males and 254 females aged 49.6 years in mean (15 to 75). Up to the end of 1988, 42 patients (4.8%) were reoperated on because of periprosthetic leakage. In primary surgery, annular calcification was found in 27 of these patients (64%), 17 patients (40%) had a bicuspid valve, and a positive culture from the excised valve was diagnosed in one of three patients with active native endocarditis. Two patients had Marfan's syndrome and two others postendocardial regurgitation. At primary surgery, mechanical prostheses were inserted in every case. Differences between the prosthetic models used could not be shown as regards to the occurrence of periprosthetic leakage. To implant the valve, interrupted everted U-mattress sutures with pledgets appeared to be the best method. Leakage occurred in 21 patients (50%) during their hospital stay and in 18 patients (43%) during the follow-up period of four months. Three others developed leakage two to four years from primary surgery. The main indication for reoperation was congestive heart failure alone or combined with heamolytic anaemia in 37 (88%) of cases. Four patients required the reoperation due to infectious dehiscence. Preoperatively, 34 patients (81%) were in NYHA (The New York Heart Association) Class III-IV. A new prosthetic valve was implanted in 23 cases, a composite graft once and in 18 cases refixation was performed. Two patients died in association with surgery, both due to the low output syndrome. During the follow-up time of 6.4 years, eight patients developed recurrent leakage. Four of them were found during their hospital stay and four others later. The role of prosthetic infection was remarkable in these eight cases; three patients with preoperative infectious dehiscence of the prosthesis had recurrence and one patient developed prosthetic endocarditis with leakage later. Three patients required more reoperations. At follow-up study, leakage was diagnosed in five of 28 living patients. Three of them were not significant and two moderate. 24 patients (86%) were in NYHA Class I-II.

Anemia, Hemolytic↗
PubMed1993

The influence of intravenous magnesium sulphate on the occurrence of atrial fibrillation after coronary artery by-pass operation.

To examine the influence of magnesium (Mg) on hypomagnesaemia and atrial fibrillation (AF) following coronary artery by-pass surgery, 140 consecutive patients were randomized to receive 70 mmol of magnesium sulphate intravenously (n = 69) or placebo (n = 71). Serum magnesium concentrations fell to 0.77 +/- 0.10 mmol.l-1 in the control group but rose to 1.09 +/- 0.17 mmol.l-1 in the Mg group (P < 0.001). The incidence of AF was 29% in the Mg group and 26% in the placebo group (NS). The AF patients were older, more of them had had prior AF episodes, their sinus rates (SR) were slower (78 +/- 10 vs 86 +/- 12 beats.min-1; P < 0.01) and serum Mg concentrations higher (0.89 +/- 0.21 vs 0.80 +/- 0.11 mmol.l-1; P < 0.05). The incidence of AF was 43% in the highest quartile of serum Mg and 23% among the rest (P = 0.056). In patients experiencing AF during the first three post-operative days, serum Mg concentrations were higher and SR slower on each day compared with non-AF patients. SR increased post-operatively less with high Mg levels (P = 0.044). In the Mg group, serum Mg and SR were the only independent predictors of AF. In conclusion, the incidence of post-operative AF is not decreased with magnesium. High Mg levels are likely to provoke AF probably by mechanisms that modify SR.

Aged↗
PubMed1993

Hydroxyethyl starch as a prime for cardiopulmonary bypass: effects of two different solutions on haemostasis.

Hydroxyethyl starch (HES) is efficacious as a volume expander in cardiac surgical patients, but it may impair the haemostatic mechanisms. However, this latter effect may be less conspicuous with low molecular weight (LMW) solutions than with high molecular weight (HMW) solutions. Therefore, LMW- and HMW-HES solutions were evaluated as priming solutions for cardiopulmonary bypass (CPB) with respect to their effect on haemostasis. Forty-five patients undergoing coronary bypass grafting were prospectively randomised to three groups and received in a double-blind manner as their CPB prime either 20 ml.kg-1 LMW-HES (Mw 120,000), 20 ml.kg-1 HMW-HES (Mw 400,000) or Ringer's acetate 2000 ml. The final volume of the prime was completed to 2000 ml with Ringer's acetate in the HES groups. Anaesthesia and CPB management were standardised. Plasma levels of von Willebrand factor antigen and factor VIII procoagulant activity were significantly more depressed after CPB in both HES-groups as compared with the crystalloid prime group. In addition, APTT was more prolonged and the maximal amplitude of thromboelastographic tracing was more decreased in the HES-groups. It is concluded that it may be advisable to avoid HES solutions in the CPB prime, especially in patients with an increased risk for bleeding after cardiac operations.

Cardiopulmonary Bypass↗
PubMed1992

Peripheral excimer laser-assisted angioplasty. Preliminary clinical experience.

A non-thermal Xenon-Chloride excimer laser was used for peripheral arterial recanalization in eight patients with obliterating atherosclerosis of the superficial femoral artery. All patients had a total occlusion with severe claudication or pain at rest. There were three complications, which all led to thrombosis of the irradiated artery. In one, the puncture site in the artery had to be closed operatively. All vessels were followed up radiographically three months after the procedure. In seven patients the vessel was patent. Several investigators have warranted caution in using thermal lasers (continuous wave Nd:YAG or argon) for angioplasty. The non-thermal excimer laser is a viable alternative--although not without problems. Initial experiences with the new device are described.

Aged↗
PubMed1992

Aortic valve replacement in patients aged over 70 years.

During a 12-year period, 58 patients aged over 70 years underwent aortic valve replacement. Sixty-six % of them had pure stenosis, 24% were with combined aortic valve disease, and six patients had only regurgitation. Preoperatively, 81% were in NYHA III and the remaining in NYHA IV. The pressure gradient in the AS-group was 105 +/- 27 mmHg and in combined-group, 99 +/- 32 mmHg. The mean ejection fraction was 54 +/- 14%. Thirty-seven mechanical and 21 biological prostheses were placed. Concomitant procedures consisted of annular dilating plasty for five patients while 16 others had coronary by-pass grafting. Hospital mortality was 12%, with the leading causes being low output syndrome and infection complications. The causes of all late deaths were non-cardiac. During the follow-up period of 2.8 +/- 2.5 years, 74% of patients with mechanical valves and 62% of patients with bioprostheses were free from late complications. Prosthetic valve endocarditis (two patients) and valve failure (one patient) occurred only in patients with tissue valves. Embolic complications were equally distributed between the groups. All patients with mechanical valves were placed on permanent anticoagulation therapy, with two of them developing significant complications. On echocardiographic examination, moderate periprosthetic leakage was found in three patients, two of them having mechanical valves. There was a significant increase in EF and regression of left ventricular hypertrophy. At follow-up examination, all 47 living patients found their performance capacity improved.

Aged↗
PubMed1991

Nd: YAG contact laser in partial nephrectomy. An experimental study in piglets.

The Nd: YAG contact laser technique with 12 W power output was used in partial nephrectomies in six piglets. Blood loss, total time and number of ligatures needed for haemostasis were compared in six partial nephrectomies performed with a steel scalpel. Mean blood loss was 53 g with the laser and 108 g with the steel scalpel (p less than 0.04). The mean time needed for haemostasis were 9.5 and 16.2 min respectively (p = 0.2) and the average number of ligatures required 1.5 and 8.8, respectively. The mean temperature rise at 5, 10 and 20 mm distance from the resection line was 5.3, 1.2 and 0.3 degrees C, respectively. The use of laser reduced blood loss and shortened the operation time. Further studies are needed concerning renal function after kidney surgery with a laser.

Animals↗
PubMed1991

Surgical treatment of infective aortic valve endocarditis.

Fifty-eight adult patients treated with aortic valve replacement for infective endocarditis were retrospectively reviewed. The operation was performed during antibiotic therapy (group I, n = 25) or after completion of such therapy, on average 17 months after diagnosis (group II, n = 33). Preoperatively 68% of group I and 24% of group II were in NYHA class IV. Bacterial aetiology was verified in 78% of all cases. Preoperative embolic complications occurred in six group I and three group II cases, causing hemiplegia in eight. At operation the aortic valve was bicuspid in 29 of the 58 patients. Vegetations and cusp perforation were present in most cases. Bacteria were demonstrated in 11 of the excised specimens. A mechanical valve prosthesis was inserted in all cases. Three patients died, one perioperatively and two during their time in hospital (2 from group I). Low-output syndrome was the commonest postoperative complication. During follow-up averaging 66 months, 12 patients died (6 of cardiac causes). Late complications were periprosthetic leakage (2 cases), significant embolism (5), and prosthetic valve endocarditis (4), causing periprosthetic leakage in one case.

Anti-Bacterial Agents↗
PubMed1990

Air contamination in open heart surgery with disposable coveralls, gowns, and drapes.

The effect of a polypropylene coverall, replacing shirt and trousers, combined with sterile laminated gowns and drapes compared with an all-cotton system was studied in regard to the dispersion of bacteria and particles in a conventionally ventilated operating theater. The operations carried out were open heart procedures in 30 adult patients. Blood agar sedimentation plates were placed in the operative, anesthesia, and perfusion areas. The mean sedimentation values during 1 hour after the start of operation were as follows in the laminate group: 63 colony-forming units (cfu)/m2 in the operative area; 77 cfu/m2 in the anesthesia area; and 143 cfu/m2 in the perfusion area. The corresponding figures in the cotton group were 350 cfu/m2, 364 cfu/m2, and 437 cfu/m2, respectively (p less than 0.0002). At the beginning of the operation, the mean values noted for colony-forming units in the air at the operative site were 8.0 cfu/m3 in the laminate group and 31 cfu/m3 in the cotton group. One hour later, the values were 10 cfu/m3 and 22 cfu/m3, respectively (p less than 0.0002). At the end of the operation, the number of particles 5 microns or larger in the air at the operative site was 278/m3 in the laminate group and 592/m3 in the cotton group. It is concluded that the use of a polypropylene coverall and laminated gowns and drapes significantly reduces the particle and bacterial contamination of the air and the bacterial sedimentation during cardiac operations.

Aged↗
PubMed1990

Indications for and risks in reoperation for coronary artery disease.

Seventy-one coronary artery bypass grafting (CABG) reoperations were performed during a 17-year period, comprising 2.7% of all CABG operations. The main indication (in 87%) was vein graft failure alone or combined with other causes. Progression of disease in native coronary arteries was the sole indication in only 4 of the 71 cases. There were seven perioperative deaths, mainly due to myocardial infarction. Significant perioperative complications arose in 36 cases, including intraoperative lesion of a previous left internal mammary graft (16.2%) or of the right ventricle or anterior descending branch of the left coronary artery (2.8%). Postoperative low output syndrome appeared in 13 patients (18.3%), in seven of whom myocardial infarction was verified. Postoperative bleeding required resternotomy in six cases (9.1%). Because of the heightened operative mortality and morbidity risks, indications for redo CABG should be individualized. A well functioning internal mammary artery graft may be a relative contraindication. Accurate knowledge of the previous operation is essential and, especially in young patients, the possibility of reoperation should be taken into consideration at initial CABG.

Adult↗
PubMed1990

Laser for harvesting of the internal mammary artery.

In 12 piglets both internal mammary arteries were dissected from the thoracic wall without a surrounding pedicle, using low-current electrocautery for one artery and continuous wave contact Nd:YAG laser (12 W) for the contralateral vessel. Changes in the arterial flow surface were evaluated by scanning electron microscopy immediately after dissection and 2 and 5 days postoperatively. Laser dissection was easier, more accurate and as fast as electrocautery. Moderate to severe degenerative changes and endothelial desquamation were seen in the electrocautery group after dissection, but lesser changes in the laser group. The changes decreased within the next 5 days, but two electrocauterized vessels showed thrombosis at 5 days. Stripping of the internal mammary artery with either method requires great care, and Nd:YAG laser offers a promising alternative to electrocautery in harvesting of that artery as a pedicled graft.

Animals↗
PubMed1990

The healing of contact Nd:YAG laser irradiated arterial wall. An experimental study in piglets.

The healing of an arterial lesion created by continuous wave contact Nd:YAG laser was investigated. Normal arterial walls were irradiated. It is nearly impossible to irradiate atheromatous plaques without involving adjacent normal arterial wall as well. The purpose of this study was to evaluate the healing process using a standard thermal laser. Different power outputs were used with 1.0 sec exposure. A cw Nd:YAG laser with a wavelength of 1064 nm was used. Eighteen piglets underwent laparotomy. An 0.6 mm fibre with a rounded 2.2 mm sapphire probe was introduced into the aorta and iliac arteries. The irradiation was performed vertically to the vessel wall. The artery specimens were studied histologically and through electron scanning microscopy. Immediately after irradiation, adherence of platelets was observed. At two days the core centre was invaded with mononuclear blood cells and polymorphonuclear leukocytes. At five days there was still some denudation of endothelium, and the initial debris started to disappear. At two weeks medial smooth muscle cells were seen around the necrotic zone. The area was encapsulated by layers of smooth muscle and collagen. The healing process seems similar to that of mechanical injury of the aortic intima.

Angioplasty, Balloon↗
PubMed1989

Right gastroepiploic artery as a coronary bypass graft.

Between November 1987 and April 1988, the right gastroepiploic artery (GEA) was used as a coronary artery bypass graft in 11 patients, 9 men and 2 women. In 1 of them, the GEA was used because no veins were available; in the others, the GEA was used to avoid the use of vein grafts. The GEA was anastomosed to the right coronary artery in all patients, and internal mammary artery grafts were used to bypass the left anterior descending and circumflex coronary arteries. All patients survived the operation. There were no early and, to date, there have been no late complications of the abdominal component of the operation. Postoperative coronary angiography showed a patent right GEA in 9 patients (82%). In 1 patient the GEA was occluded, probably because of an enlarged liver. If the long-term patency of right GEA grafts is similar to that of internal mammary artery grafts, wider use of this viable graft is indicated.

Adult↗
PubMed1989

Is electrocautery safe for internal mammary artery (IMA) mobilization? A study using scanning electron microscopy (SEM).

Being the graft of choice, the internal mammary artery (IMA) is increasingly used for coronary artery bypass grafting. Presently, electrocautery is liberally used to mobilize both IMAs. Preservation of IMA flow surface was evaluated by scanning electron microscopy (SEM) after mobilization with either sharp dissection or electrocautery in five clinical patients undergoing coronary artery bypass surgery. Major side branches were secured with metallic clips. Specimens for SEM were harvested after heparinization but before institution of cardiopulmonary bypass from the terminal branches of both IMAs after they had been skeletonized with either mobilization method. When mobilization of the IMA was performed as a pedicle, the flow surface was well preserved in both groups. However, if a contact of the electrocautery blade with the wall of the IMA or with a metallic clip parallell to the wall was allowed, a clearly visible zone of endothelial damage, sometimes associated with mural trombus formation was observed. In conclusion, caution is needed with electrocautery. Thermal injuries of the IMA may remain undetected during surgery and cause graft occlusion later.

Electrocoagulation↗