Kenneth Nordstrand

Transmyocardial revascularization with CO2 laser in patients with refractory angina pectoris ☆: Clinical results from The Norwegian Randomized Trial

OBJECTIVES The purpose of the study was to evaluate clinical effects, exercise performance and effect on maximal oxygen consumption (MVO2) of transmyocardial revascularization with CO2-laser (TMR) in patients with refractory angina pectoris. BACKGROUND Transmyocardial laser revascularization is a new method to treat patients with refractory angina pectoris not eligible for conventional revascularization. Few randomized studies comparing TMR with conventional treatment have been published. METHODS One hundred patients with refractory angina not eligible for conventional revascularization were block-randomized in a 1:1 ratio to receive continued optimal medical treatment (MT) or TMR in addition to MT. The patients were evaluated at baseline and at three and 12 months with end points to symptoms, exercise capacity and MVO2. RESULTS Transmyocardial laser revascularization resulted in significant relief in angina symptoms after three and 12 months compared to baseline. Time to chest pain during exercise increased from baseline by 78 s after three months (p = NS) and 66 s (p < 0.01) after 12 months in the TMR group, whereas total exercise time and MVO2 were unchanged. No significant changes were observed in the MT group. Perioperative mortality was 4%. One year mortality was 12% in the TMR group and 8% in the MT group (p = NS.) CONCLUSIONS Transmyocardial laser revascularization was performed with low perioperative mortality and caused significant symptomatic improvement, but no improvement in exercise capacity.

The effect of dexamethasone on side effects after coronary revascularization procedures.

Corticosteroids decrease side effects after noncardiac elective surgery. We designed this randomized, double-blinded, placebo-controlled study to test the hypothesis that standard doses of dexamethasone (4 mg ×2) would reduce postoperative nausea, vomiting, and pain, decrease the incidence of atrial fibrillation (AF), and improve appetite after cardiac surgery, thereby facilitating the recovery process. A total of 300 patients undergoing coronary revascularization surgery were enrolled in this clinical study. The anesthetic management was standardized in all patients. Dexamethasone (4 mg/mL) or saline (1 mL) was administered after the induction of anesthesia and a second dose of the same study drug was given on the morning after surgery. The incidence of AF was determined by analyzing the first 72 h of continuously recorded electrocardiogram records after cardiac surgery. The patients were assessed at 24- and 48-h intervals after surgery, as well as at the time of hospital discharge, to determine the incidence and severity of postoperative side effects (e.g., nausea, vomiting, pain) and patient satisfaction scores. Dexamethasone significantly reduced the need for antiemetic rescue medication on the first postoperative day (30% versus 42%), and the incidences of nausea (15% versus 26%) and vomiting (5% versus 16%) on the second postoperative day (P < 0.05). In addition, dexamethasone significantly reduced the percentage of patients with a depressed appetite on the second postoperative day. However, the corticosteroid failed to decrease the incidence of AF (27% versus 32%) or the total dosage of opioid analgesic medication administered in the postoperative period. We conclude that dexamethasone (8 mg in divided doses) was beneficial in reducing emetic symptoms and improving appetite after cardiac surgery. However, this dose of the corticosteroid does not seem to have antiarrhythmic or analgesic-sparing properties. IMPLICATIONS: Dexamethasone (8 mg IV) was beneficial in reducing emetic symptoms and increasing appetite after cardiac surgery. However, this dose of the corticosteroid failed to decrease postoperative pain or the incidence of new-onset atrial fibrillation.

Is atrial fibrillation caused by extracorporeal circulation

BACKGROUND Atrial fibrillation is the most common rhythm disturbance encountered after open heart operations, with a reported incidence up to 40%. Despite its high incidence and clinical relevance its etiology remains obscure. It has been hypothesized that atrial fibrillation might be related to extracorporeal circulation. We performed a retrospective study (January 1, 1997 to December 31, 1997) comparing the incidence of atrial fibrillation in 3 groups of patients revascularized with and without extracorporeal circulation. METHODS The first group comprised patients with coronary artery disease operated on with standard revascularization technique with cardiopulmonary bypass (n = 685). The second group included patients who had minimally invasive coronary artery bypass grafting without the use of extracorporeal circulation (n = 19). Patients in the third group had off-pump transmyocardial laser revascularization (n = 19). RESULTS There was no significant difference in the incidence of atrial fibrillation in the group that had conventional coronary artery bypass and the group that had minimally invasive coronary artery bypass without cardiopulmonary bypass. The incidence of atrial fibrillation was significantly lower in the transmyocardial laser group compared with the other two groups. CONCLUSIONS The present study found that postoperative atrial fibrillation is not caused solely by extracorporeal circulation, but patients who had transmyocardial laser revascularization had a significantly lower incidence of atrial fibrillation.

The CarboMedics valve: midterm follow-up with analysis of risk factors.

BACKGROUND This study examined the midterm results with the CarboMedics prosthetic valve. METHODS From 1987 through 1991 a total of 569 patients received the CarboMedics prosthesis. RESULTS Early mortality was 4.9% and related to emergency operation, presence of diabetes mellitus, coronary artery disease, preoperative New York Heart Association class, duration of cardiopulmonary bypass, and aortic cross-clamp time. Midterm follow-up with respect to mortality was 100% complete. All patients were followed up in the hospital after 1 year. In addition 86% of the patients responded to a questionnaire. Mean follow-up was 3 years (range, 0 to 5.6 years). Cumulative survival at 1 and 4 years was 91.2% +/- 1.2% and 83.7% +/- 1.8%, respectively. Five patients experienced obstructive valve thrombosis (0.3%/patient-year), 16 patients had major thromboembolic events (0.9%/patient-year), and 10 patients had major warfarin-related bleeding (0.6%/patient-year) requiring hospitalization or blood transfusions. Eight patients were reoperated on for paraprosthetic leak (0.4%/patient-year). Prosthetic valve endocarditis developed in 4 patients (0.2%/patient-year). No structural valve failure was observed. CONCLUSIONS Midterm follow-up demonstrates that the CarboMedics mechanical prosthesis is reliable and has an acceptable rate of valve-related complications.

Lipid entrapment and cellular changes in the rat myocard, lung and liver after long‐term parenteral nutrition with lipid emulsion:

We have demonstrated organ damage after long‐term administration of lipid‐based parenteral nutrition, possibly initiated by intravascular pooling of lipid and phagocytes, in both rats and pigs. To evaluate whether accumulation of lipid could simply be caused by mechanical filtration, a comparative study of three separate capillary beds was performed. Rats were given lipid emulsion (n = 5) or isotonic saline (n=4) through central venous catheters for 3 weeks. Using both light and electron microscopy, lipid accumulation and structural changes in the rat myocard were compared to those in the lung and liver. The study provides evidence that within myocardial capillaries both peripheral blood monocytes and endothelial cells performed phagocytosis of lipid droplets following administration of lipid emulsion, but no large‐scale intravascular pooling of lipid resulted. Morphometry of the myocard detected no lipid increase in the myocytes from the rats given lipid emulsion compared with controls and in neither were there any stigmata of vasculitis or myocardial damage, in contrast to the lung and liver, where intravascular pooling of lipid and phagocytes was seen. This indicates that phagocytosis was an important mechanism involved in entrapment and elimination of lipid.

Effects of transmyocardial revascularization on myocardial perfusion and systolic function assessed by nuclear and magnetic resonance imaging methods.

Objective - There is no obvious explanation, except placebo, to the symptomatic effect of transmyocardial laser revascularization (TMR) in patients with refractory angina. Whether TMR improves myocardial perfusion or relieves symptoms without altering cardiac function is not clarified. Methods - One hundred patients with refractory angina were randomized 1:1 to TMR (CO2 laser) and medical treatment, or medical treatment alone. Technetium 99m (99mTc)-tetrofosmin myocardial perfusion tomography (SPECT), quantitative myocardial perfusion gated SPECT (QGSPECT), technetium 99m (99mTc) multiple gated acquisition radionuclide ventriculografi (MUGA) and cine-magnetic resonance imaging (cine-MRI) were performed at baseline and after 3 and 12 months. Results - Following TMR, a slight reduction in left ventricular ejection fraction (LVEF) (p < 0.05) was observed (MUGA and QGSPECT) compared to baseline. Inclusion of incomplete studies (QGSPECT) revealed a significant reduction in LVEF and increase in left ventricular end-diastolic volume (LVEDV) (p < 0.05) compared to a control group. Otherwise, no between-group comparisons showed statistically significant differences. Conclusion - TMR did not improve myocardial perfusion, but led to a reduction in LVEF and increase in LVEDV, however not significantly different from the control group.OBJECTIVE There is no obvious explanation, except placebo, to the symptomatic effect of transmyocardial laser revascularization (TMR) in patients with refractory angina. Whether TMR improves myocardial perfusion or relieves symptoms without altering cardiac function is not clarified. METHODS One hundred patients with refractory angina were randomized 1:1 to TMR (CO2 laser) and medical treatment, or medical treatment alone. Technetium 99m (99mTc)-tetrofosmin myocardial perfusion tomography (SPECT), quantitative myocardial perfusion gated SPECT (QGSPECT), technetium 99m (99mTc) multiple gated acquisition radionuclide ventriculografi (MUGA) and cine-magnetic resonance imaging (cine-MRI) were performed at baseline and after 3 and 12 months. RESULTS Following TMR, a slight reduction in left ventricular ejection fraction (LVEF) (p < 0.05) was observed (MUGA and QGSPECT) compared to baseline. Inclusion of incomplete studies (QGSPECT) revealed a significant reduction in LVEF and increase in left ventricular end-diastolic volume (LVEDV) (p < 0.05) compared to a control group. Otherwise, no between-group comparisons showed statistically significant differences. CONCLUSION TMR did not improve myocardial perfusion, but led to a reduction in LVEF and increase in LVEDV, however not significantly different from the control group.

Perioperative cardiac function and predictors for adverse events after transmyocardial laser treatment

BACKGROUND Previous studies have reported that mortality and morbidity after transmyocardial laser treatment (TML) mainly occur perioperatively. The present study was designed to evaluate left-ventricular function and identify risk factors for cardiac-related adverse events in this phase. METHODS Forty-nine patients were studied. The inclusion criteria were angina pectoris Canadian Cardiovascular Society Angina Score (CCSAS) class III and IV refractory to medical therapy and untreatable by coronary artery bypass graft or percutaneous transluminal coronary angioplasty, age less than 75 years, left ventricular ejection fraction greater than or equal to 30%, and myocardial regions with reversible ischemia. Hemodynamic data and cardiac adverse events were registered. The follow-up time was 30 days. RESULTS A transient decrease in mean cardiac index (CI) was observed, reaching its minimum immediately after end of the surgical procedure (1.8+/-0.4, p<0.01 vs. baseline). Two patients (4%) died during the postoperative period (30 days). Seventeen patients (35%) experienced adverse cardiac-related events, where CCSAS class IV, unprotected left main stem stenosis, and diabetes mellitus were identified as risk factors in a multivariate analysis. CONCLUSIONS A transient impairment of left ventricular function was observed after TML. The morbidity and mortality after TML were almost exclusively cardiac-related, identifying CCSAS class IV, unprotected left main stem stenosis, and diabetes as risk factors.

Development of granulomas and vascular fibrocellular proliferation in the lungs of pigs receiving long‐term lipid‐based parenteral nutrition

The lungs of pigs receiving long‐term total parenteral nutrition (TPN) have been studied. A total of 20 pigs were tentatively infused with TPN through central venous catheters for 7 weeks. To secure adequate nutrition and gastrointestinal absorbance of nutrients, an additional full oral diet was given to eight of these animals. Fifteen control animals received Ringer solution through central venous catheters in addition to the oral diet. All animals infused with TPN for 7 weeks developed lung granulomas, a finding not observed in control animals. No lung granulomas were seen in three TPN animals sacrificed after 3 to 5 weeks owing to illness. All TPN animals also developed tissue reactions suggesting long‐standing lung vascular inflammation. Similar vascular changes were seen in seven control animals that had bacterial infection or endotoxemia. The total amount of neutral fat in lung homogenate tended to increase in animals given TPN, and the linoleic acid content was significantly increased. In conclusion, long‐term TPN caused lung granulomas in pigs. Vascular damage seemed to be accelerated by bacterial infection as well as by the TPN. The tissue reactions presumably involved long‐term activation of monocytes/macrophages.

Pulmonary intravascular macrophages appear in rats after long-term administration of lipid emulsion and amino acid solution

Intravascular macrophages have rarely been seen in normal lungs of humans and rats, but in rats endotoxaemia has induced their presence. To study whether substrates used for parenteral nutrition could have a similar stimulatory effect on mononuclear phagocytes, rats were given lipid emulsion (n=5), amino acid solution (n=5), or isotonic saline (n=5) through central venous catheters for 3 weeks. Structural changes in the lung microvessels were evaluated using electron microscopy. The areal fraction of pulmonary intravascular mononuclear phagocytes was 19.6% (SD=8.2) in rats given lipid emulsion (p<0.05) and 8.2% (SD=8.2) in rats given amino acid solution n.s. compared to 2.4% (SD= 4.0) in rats given saline. The increase in areal fraction was mainly due to an increase in cell numbers. In rats given lipid emulsion the intravascular phagocytes were only slightly larger than in rats given saline, but had the morphological features of mature macrophages. The study demonstrates that lipid emulsion recruits pulmonary intravascular macrophages in rats, indicating a stimulatory effect on the mononuclear phagocyte system. The effect was less pronounced with amino acid solution.

Retrograde Internal Mammary Artery as Coronary Bypass: A Prospective Study with Postoperative Angiographic Evaluation

Although the internal mammary artery (IMA) as a coronary graft offers better long-term patency than the saphenous vein, a factor limiting its use has been the length of the arterys pedicle. In an attempt to overcome this limitation, we evaluated the use of retrograde right IMA in a prospective study. In ten patients scheduled for routine coronary artery bypass surgery, bilateral IMA grafting was used, the left IMA in routine fashion, but the right IMA dissected from the level of the first rib, cut there and placed as an inverted graft. Three months postoperatively the patients were clinically evaluated with stress exercise test (n = 10) and coronary angiography (n = 9). No patient had recurrence of angina. Angiography revealed patency of the retrograde right IMA graft in six of nine patients. On the basis of these data we do not recommend routine use of retrograde IMA.