Randomised comparison of provisional side branch stenting versus a two-stent strategy for treatment of true coronary bifurcation lesions involving a large side branch: the Nordic-Baltic Bifurcation Study IV

Background

It is still uncertain whether coronary bifurcations with lesions involving a large side branch (SB) should be treated by stenting the main vessel and provisional stenting of the SB (simple) or by routine two-stent techniques (complex). We aimed to compare clinical outcome after treatment of lesions in large bifurcations by simple or complex stent implantation.

Methods

The study was a randomised, superiority trial. Enrolment required a SB≥2.75 mm, ≥50% diameter stenosis in both vessels, and allowed SB lesion length up to 15 mm. The primary endpoint was a composite of cardiac death, non-procedural myocardial infarction and target lesion revascularisation at 6 months. Two-year clinical follow-up was included in this primary reporting due to lower than expected event rates.

Results

A total of 450 patients were assigned to simple stenting (n=221) or complex stenting (n=229) in 14 Nordic and Baltic centres. Two-year follow-up was available in 218 (98.6%) and 228 (99.5%) patients, respectively. The primary endpoint of major adverse cardiac events (MACE) at 6 months was 5.5% vs 2.2% (risk differences 3.2%, 95% CI −0.2 to 6.8, p=0.07) and at 2 years 12.9% vs 8.4% (HR 0.63, 95% CI 0.35 to 1.13, p=0.12) after simple versus complex treatment. In the subgroup treated by newer generation drug-eluting stents, MACE was 12.0% vs 5.6% (HR 0.45, 95% CI 0.17 to 1.17, p=0.10) after simple versus complex treatment.

Conclusion

In the treatment of bifurcation lesions involving a large SB with ostial stenosis, routine two-stent techniques did not improve outcome significantly compared with treatment by the simpler main vessel stenting technique after 2 years.

Trial registration number

NCT01496638.

Are the guidelines for treatment of myocardial infarction complied with?

BACKGROUND

New guidelines recommend early invasive evaluation and treatment for most patients with acute myocardial infarction--including patients with myocardial infarction without ST elevation in the ECG. This study examines compliance with the new guidelines at Sørlandet Hospital Arendal.

MATERIAL AND METHOD

All patients admitted to Sørlandet Hospital Arendal with acute myocardial infarction in 2012 were registered in the Norwegian Myocardial Infarction Register. Data from the register were used to analyse the time that passed from symptom onset to coronary angiography and revascularisation.

RESULTS

In 2012, 788 patients were admitted to Sørlandet Hospital Arendal with acute myocardial infarction. Of these, 269 (34.1%) had ST elevation mycardial infarction (STEMI) and 519 (65.9%) had non-ST elevation myocardial infarction (NSTEMI). Most patients with ST elevation infarction (220 (81.8%)) were admitted directly to Sørlandet Hospital Arendal, and the median time from admission to revascularisation was 31 minutes. 347 (66.9%) of the patients with non-ST elevation infarction were first admitted to a local hospital before being transferred to Sørlandet Hospital Arendal. Only four (1.2%) of them underwent angiography within two hours of admission to the first hospital. 13 (9.0%) of the patients with non-ST elevation infarction who were admitted directly and underwent angiography (n = 144) had an angiogram within two hours of admission. Angiography was performed within 24 hours in 119 (34.3%) of those transferred (n = 347) and in 82 (56.9%) of the directly admitted patients who underwent angiography (n = 144).

INTERPRETATION

Many patients with non-ST elevation infarction did not receive revascularisation with percutaneous coronary intervention (PCI) within the recommended time frame. Where there is a strong clinical suspicion of acute myocardial infarction, more patients should be admitted directly to hospitals with PCI preparedness.

Clinical outcome after crush versus culotte stenting of coronary artery bifurcation lesions: the Nordic Stent Technique Study 36-month follow-up results

OBJECTIVES

The aim of the study was to compare long-term follow-up results of crush versus culotte stent techniques in coronary bifurcation lesions.

BACKGROUND

The randomized Nordic Stent Technique Study showed similar 6-month clinical and 8-month angiographic results with the crush and culotte stent techniques of de novo coronary artery bifurcation lesions using sirolimus-eluting stents. Here, we report the 36-month efficacy and safety of the Nordic Stent Technique Study.

METHODS

A total of 424 patients with a bifurcation lesion were randomized to stenting of both main vessel and side branch with the crush or the culotte technique and followed for 36 months. Major adverse cardiac events-the composite of cardiac death, myocardial infarction, stent thrombosis, or target vessel revascularization-were the primary endpoint.

RESULTS

Follow-up was complete for all patients. At 36 months, the rates of the primary endpoint were 20.6% versus 16.7% (p = 0.32), index lesion restenosis 11.5% versus 6.5% (p = 0.09), and definite stent thrombosis 1.4% versus 4.7% (p = 0.09) in the crush and the culotte groups, respectively.

CONCLUSIONS

At 36-month follow-up, the clinical outcomes were similar for patients with coronary bifurcation lesions treated with the culotte or the crush stent technique. (Nordic Bifurcation Study. How to Use Drug Eluting Stents [DES] in Bifurcation Lesions? NCT00376571).

Ten years of infective endocarditis: a clinicopathologic study

The records of 46 patients with infective endocarditis diagnosed either clinically or post-mortem were analyzed. Twenty-six patients were over 60 years of age. S. aureus was the predominant organism, almost exclusively found in patients with acute endocarditis. Thirty-six patients had pre-existing heart disease, the most common being non-rheumatic valvular calcification and congenital defects. Two thirds of the patients, especially those with aortic valve regurgitation, developed new or progressive heart failure. A correct clinical diagnosis was established in only 30 patients. Twenty-three patients died, the mortality being 71% in acute and 32% in subacute disease. Only one of eight patients with prosthetic valve infection died. Four patients required urgent valve replacement. Early surgical intervention should be considered in patients with uncontrolled heart failure.

Randomized comparison of coronary bifurcation stenting with the crush versus the culotte technique using sirolimus eluting stents: the Nordic stent technique study

BACKGROUND

In a number of coronary bifurcation lesions, both the main vessel and the side branch need stent coverage. Using sirolimus eluting stents, we compared 2 dedicated bifurcation stent techniques, the crush and the culotte techniques in a randomized trial with separate clinical and angiographic end-points.

METHODS AND RESULTS

A total of 424 patients with a bifurcation lesion were randomized to crush (n=209) and culotte (n=215) stenting. The primary end point was major adverse cardiac events; cardiac death, myocardial infarction, target vessel revascularization, or stent thrombosis after 6 months. At 6 months there were no significant differences in major adverse cardiac event rates between the groups; crush 4.3%, culotte 3.7% (P=0.87). Procedure and fluoroscopy times and contrast volumes were similar in the 2 groups. The rates of procedure-related increase in biomarkers of myocardial injury were 15.5% in crush versus 8.8% in culotte group (P=0.08). A total of 324 patients had a quantitative coronary assessment at the index procedure and after 8 months. The angiographic end-points of in-segment and in-stent restenosis of main vessel and/or side branch after 8 months were found in 12.1% versus 6.6% (P=0.10) and in 10.5% versus 4.5% (P=0.046) in the crush and culotte groups, respectively.

CONCLUSIONS

Both the crush and the culotte bifurcation stenting techniques were associated with similar and excellent clinical and angiographic results. Angiographically, there was a trend toward less in-segment restenosis and significantly reduced in-stent restenosis following culotte stenting.

Randomized study on simple versus complex stenting of coronary artery bifurcation lesions: the Nordic bifurcation study

BACKGROUND

The optimal stenting strategy in coronary artery bifurcation lesions is unknown. In the present study, a strategy of stenting both the main vessel and the side branch (MV+SB) was compared with a strategy of stenting the main vessel only, with optional stenting of the side branch (MV), with sirolimus-eluting stents.

METHODS AND RESULTS

A total of 413 patients with a bifurcation lesion were randomized. The primary end point was a major adverse cardiac event: cardiac death, myocardial infarction, target-vessel revascularization, or stent thrombosis after 6 months. At 6 months, there were no significant differences in rates of major adverse cardiac events between the groups (MV+SB 3.4%, MV 2.9%; P=NS). In the MV+SB group, there were significantly longer procedure and fluoroscopy times, higher contrast volumes, and higher rates of procedure-related increases in biomarkers of myocardial injury. A total of 307 patients had a quantitative coronary assessment at the index procedure and after 8 months. The combined angiographic end point of diameter stenosis >50% of main vessel and occlusion of the side branch after 8 months was found in 5.3% in the MV group and 5.1% in the MV+SB group (P=NS).

CONCLUSIONS

Independent of stenting strategy, excellent clinical and angiographic results were obtained with percutaneous treatment of de novo coronary artery bifurcation lesions with sirolimus-eluting stents. The simple stenting strategy used in the MV group was associated with reduced procedure and fluoroscopy times and lower rates of procedure-related biomarker elevation. Therefore, this strategy can be recommended as the routine bifurcation stenting technique.

Clinical benefit of small vessel stenting: one-year follow-up of the SISCA trial

OBJECTIVE

To assess the long-term clinical benefit of elective stenting as compared with percutaneous transluminal coronary angioplasty (PTCA) in small coronary arteries.

DESIGN

The Stenting in Small Coronary Arteries (SISCA) trial was a randomized trial comparing elective stenting with PTCA in coronary arteries with a reference diameter of 2.1-3.0 mm. The heparin-coated beStent was used. Control angiography was performed after 6 months, and the patients were followed clinically for 12 months.

RESULTS

At 6 months the clinical outcome was significantly better in the stent group as compared with the PTCA group, with an event-free survival in 90.5 and 76.1% (p = 0.016), respectively. From 6 to 12 months, event-free survival was unchanged in both groups, demonstrating a sustained long-term clinical benefit of elective stenting.

CONCLUSION

Angioplasty in small coronary arteries is associated with a favorable clinical outcome after 1 year. The clinical benefit of elective stenting using the Hepamed-coated beStent is maintained beyond 6 months, without any tendency towards late events. Thus, elective stenting should be considered as an option when treating small coronary arteries.

[Long-term results with the left internal mammary artery as coronary bypass]

BACKGROUND

From 1986 we have routinely used the left internal mammary artery instead of autologous vein as bypass to the left anterior descending coronary artery.

MATERIAL AND METHODS

A cohort of 52 patients has been followed up for up to 12 years. Six years postoperatively, 40 patients were evaluated by clinical examination, exercise testing and serum lipid assessment. Of these, 38 underwent angiography of the native coronary arteries and of all grafts, which represented 47 left internal mammary artery, 90 saphenous vein, and 3 right internal mammary artery bypasses. Information regarding angina recurrence and the need for repeated revascularisation was obtained from hospital records. Twelve-year mortality data were provided by public registers.

RESULTS

Fifty patients were discharged alive. Two serious complications, of which one was fatal, were directly related to the use of the left internal mammary artery. After six years, all the re-examined patients had improved their exercise tolerance; 25 (63%) were angina-free. 44 (94%) left internal mammary artery and 67 (74%) saphenous vein bypasses were patent. Tobacco consumption was considerably reduced over the first six years postoperatively while mean triglyceride and cholesterol levels remained moderately elevated. After 12 years, 18 patients were deceased, half of them from coronary heart disease.

INTERPRETATION

Our results are in accordance with large, international studies.

Stenting in small coronary arteries (SISCA) trial. A randomized comparison between balloon angioplasty and the heparin-coated beStent

OBJECTIVES

The purpose of this study was to assess the clinical and angiographic benefits of elective stenting in coronary arteries with a reference diameter of 2.1 to 3.0 mm, as compared with traditional percutaneous transluminal coronary angioplasty (PTCA).

BACKGROUND

The problems related to small-vessel stenting might be overcome using modern stents designed for small vessels, combined with effective antiplatelet therapy.

METHODS

In five centers, 145 patients with stable or unstable angina were randomly assigned to elective stenting treatment with the heparin (Hepamed)-coated beStent or PTCA. Control angiography was performed after six months. The primary end point was the minimal lumen diameter (MLD) at follow-up. Secondary end points were the restenosis rate, event-free survival and angina status.

RESULTS

At follow-up, there was a trend toward a larger MLD in the stent group (1.69 +/- 0.52 mm vs. 1.57 +/- 0.44 mm, p = 0.096). Event-free survival at follow-up was significantly higher in the stent group: 90.5% vs. 76.1% (p = 0.016). The restenosis rate was low in both groups (9.7% and 18.8% in the stent and PTCA groups, respectively; p = 0.15). Analyzed as treated, both the MLD and restenosis rate were significantly improved in patients who had stents as compared with PTCA.

CONCLUSIONS

In small coronary arteries, both PTCA and elective stenting are associated with good clinical and angiographic outcomes after six months. Compared with PTCA, elective treatment with the heparin-coated beStent improves the clinical outcome; however, there was only a nonsignificant trend toward angiographic improvement.

Magnum wire for percutaneous coronary balloon angioplasty in 800 total chronic occlusions

The experience in consecutive procedures with 800 recanalization attempts of chronic total coronary occlusions using the Magnum wire was analyzed from a prospectively constituted computerized database. The data confirm that the Magnum wire, generally used as a primary intervention for occlusive angioplasty at our centers, is competitive with conventional systems in this setting.

Magnum wire for angioplasty of total and non-total coronary lesions

The magnum wire is a stiff-shaft, blunt-tip wire constructed for recanalisation during angioplasty. Smaller series have demonstrated superior qualities compared to conventional wires. The purpose of this study was to analyze its feasibility in a larger number of procedures. A single centre database analysis identified the use of Magnum wire during 443 procedures accounting for 26% of all angioplasties from October 1992 to February 1995. There were 347 total occlusions and 222 non-total lesions. Technical success was 69% in total and 90% in non-total lesions, whereas angiographic success was 58% and 75%, respectively. Stents were successfully implanted in 48 lesions; in 29 (8%) total occlusions and 19 (9%) non-total lesions. The total occlusion-related complication rate was 1.7%. Acute closure occurred in 4.1% of non-total lesions. In conclusion, Magnum wire is a feasible tool for angioplasty of total occlusions and severe stenoses. It is a cheap, simple and safe method for recanalisation.

Pattern of coronary artery disease in patients with ventricular tachycardia and fibrillation exposed by exercise-induced ischemia

The majority of patients with serious exercise-induced ventricular arrhythmias have extensive coronary artery disease. These arrhythmias develop, however, only in a minority of patients with angina pectoris. The purpose of the present study was therefore to investigate whether these arrhythmia patients are characterized by any specific "arrhythmogenic" pattern of coronary artery disease. Among 1100 consecutive patients undergoing coronary artery bypass grafting, 30 (2.7%) patients had ventricular tachycardia or fibrillation during preoperative exercise testing. For each of these patients, two matched controls with angina pectoris but no ventricular arrhythmia were selected. All patients underwent angiocardiography by standard techniques. The recordings were blinded and interpreted in random order by an experienced invasive cardiologist. Significant stenosis (> or = 50%) of the main left coronary artery was found in 27% of the case patients compared to 12% of the matched controls (p = 0.069, two-tailed t test); proximal left anterior descending artery stenoses were more frequent in the arrhythmia patients. Although stenosis > or = 75% was only moderately more frequent in the case patients, the difference was highly significant for stenosis > or = 95%, which was seen in 47% of the case patients compared to 22% of the controls (p = 0.015). The difference was even more pronounced for the combination of main left coronary artery stenosis and/or high-grade stenosis (> or = 95%) of the left anterior descending artery. This pattern was seen in 60% of the case patients compared to 28% of the matched controls (p = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical revascularization in the treatment of ventricular tachycardia and fibrillation exposed by exercise-induced ischaemia

The role of myocardial revascularization in the treatment of malignant ventricular arrhythmias is not well defined. Our hypothesis was that in patients with ventricular tachycardia or fibrillation exposed by exercise-induced ischaemia, the acute transient ischaemia plays a principal causal role, and that in these patients surgical myocardial revascularization alone might be an effective treatment. Among 1100 consecutive patients undergoing isolated coronary artery bypass surgery (CABG) 30 patients (2.7%) characterized by ventricular tachycardia or fibrillation at the symptom-limited exercise tests prior to revascularization were studied prospectively. All patients had exercise-induced angina pectoris or ischaemic ST-segment depression preceding at least one of the arrhythmic events. In addition, eight of these 30 patients had experienced syncope during out-of-hospital exertional activities. After surgical revascularization, the 28 patients surviving to hospital discharge were followed for 1.6 to 86 months (mean 29 +/- 29 months) as outpatients and underwent between one to eight exercise tests (mean 2.6 +/- 1.9). One of these patients died suddenly of unknown causes at 14 months, another from cancer at 53 months. Twenty-six patients experienced a total of 34 episodes of ventricular tachycardia before revascularization. Two of these patients, both having residual ischaemia, had arrhythmia recurrences during follow-up; odds ratio (OR) 84.5, 95% confidence interval (CI) 18.7-381.9; P = < 0.010. Exercise-induced ventricular fibrillation occurred in eight patients pre-operatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiographic restenosis after successful Wallstent stent implantation: an analysis of risk predictors

Follow-up angiographic study was performed in 86 patients after initially successful Wallstent stent (Medinvent, Lausanne, Switzerland) implantation between April 1986 and October 1990. The stent angiographic restenosis rate was 16% at a mean of 8 months after stenting despite the inclusion of a substantial number of patients at high risk of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Of a total 15 variables analyzed, only suboptimal stent placement was found to be a significant predictor of stent restenosis. Age; gender; baseline New York Heart Association functional class; previous PTCA; indication for stenting; left ventricular ejection fraction; preangioplasty and immediate postangioplasty diameter stenosis severity; stented vessel site, lesional morphology; number, diameter, and length of stents implanted; and the interval between stenting and follow-up angiographic restudy were not significant risk factors of stent restenosis. Our study suggests that intracoronary stent implantation with the Wallstent may be a useful and promising adjunctive option after PTCA, particularly in patients at high risk of restenosis after PTCA. However, because of the significantly enhanced risk of restenosis after suboptimal stent implantation, we strongly recommend the selection and placement of Wallstent stents that adequately cover the entire length of the dilated coronary segment.

[Arteria gastroepiploica dextra in coronary surgery. Complete revascularization in angina pectoris]

We have used the right gastroepiploic artery as a viable jump graft to the distal right coronary artery in two patients. The first patient was a 37 year-old man with recurrent angina after coronary bypass surgery with three vein grafts eight years previously. The second patient was a man aged 45 with angina in New York Heart Association Class III to IV. In both cases coronary angiography revealed severe triple vessel disease with multiple proximal and distal occlusions or stenosis. Both internal mammary arteries were also used in the two patients to revascularize the LAD and circumflex systems. Thus, a complete revascularization was achieved by use of only viable arteries as conduits. Both patients recovered well and were free from angina. At present only the first patient has had a postoperative angiogram, which showed good patency of the gastroepiploic artery jump graft. If the long-term patency of this type of graft is similar to that of the internal mammary arteries, it is another suitable arterial conduit for revascularization of the ischemic myocardium.

Cardiac effects of secretin; an approach to its mechanisms of action as shown by beta-adrenergic blockade and measurement of left ventricular dimensions in dogs

In previous studies, the peptide secretin has demonstrated the ability to increase cardiac output and peripheral organ flow. In this investigation the mechanisms of the myocardial effects of secretin were studied. The secretin effects on cardiac output, stroke volume and systemic resistance were unaltered after propranolol, whereas the effect on LVdP/dt was reduced and the heart rate effect negligible. Systemic pressure, myocardial blood flow and myocardial oxygen consumption were unchanged by secretin infusion both before and after beta-receptor blockade. Secretin caused reduction of all three end-systolic left ventricular diameters. Thus, an inotropic effect by secretin was confirmed. Beta-receptor blockade reduced the inotropic effect and almost abolished the chronotropic effect, whereas the vasodilating effect was unaltered. The main haemodynamic effect of secretin was caused by activation of receptors other than the beta-adrenergic receptors.

Inosine causing insulin release and increased myocardial uptake of carbohydrates relative to free fatty acids in dogs

The aim of the present study was to determine the effect of i.v. inosine on myocardial substrate uptake and function in the in situ dog heart. Inosine was infused i.v. at a rate of 5 mg kg min-1 in eight closed-chest pentobarbital anaesthetized dogs. Inosine caused a 46% decrease (P less than 0.01) in plasma free fatty acids (FFA), a 15% decrease (P less than 0.05) in plasma glycerol, an 18% decrease (P less than 0.05) in plasma glucose and a 46% increase (P less than 0.01) in blood lactate. This was associated with a 55% decrease (P less than 0.01) in myocardial FFA uptake and a 72% increase in lactate uptake, while glucose uptake remained unchanged. These metabolic changes were associated with a five-fold increase (P less than 0.05) in arterial insulin. Inosine caused an 18% increase (P less than 0.01) in myocardial blood flow without changing MVO2. There was a 33% increase (P less than 0.01) in LV dP/dtmax, a decrease in LVEDP from 4.9 +/- 0.9 (mean +/- SEM) to 0.9 +/- 0.3 mmHg (P less than 0.05) and a 24% decrease (P less than 0.01) in systemic vascular resistance. Inosine caused a transient 38% increase (P less than 0.05) in pulmonary vascular resistance. In conclusion, in addition to a positive inotropic effect and vascular effects inosine was found to cause release of insulin and to shift myocardial metabolism towards increased uptake of carbohydrates relative to FFA.

Peripheral distribution of the increased cardiac output by secretin during acute ischemic left ventricular failure

Secretin, a 27-amino acid peptide with both vasodilating and inotropic properties, was investigated according to its effects on peripheral flow distribution in acute ischemic left ventricular failure accomplished by embolization of the left coronary artery in anesthetized dogs. Electromagnetic monitoring of renal, carotid, femoral and superior mesenteric artery flow was used. During the induction of heart failure a general reduction of flow with preponderance of that of the carotid and femoral arteries occurred. The secretin infusion caused increases in renal flow by 58%, carotid flow by 63%, femoral flow by 50% and superior mesenteric flow by 34%. The corresponding reductions in arterial resistances were 33, 35, 31 and 24%, respectively. Compared to levels before induction of failure, restoration of flow in all arteries as well as cardiac output was achieved, with exception of renal flow that was 25% higher. The arterial pressure was not altered and a modest inotropic effect of secretin was confirmed. It was concluded that in acute left ventricular failure secretin caused a general distribution of the increased cardiac output in the arteries investigated with a preponderance of renal artery flow.

Effects of beta-receptor blockade on regional blood flows during acute left ventricular failure in dogs

This study describes the effects of beta-receptor blockade on systemic hemodynamics and regional blood flows during acute ischemic heart failure in dogs. Depression of left ventricular (LV) function was induced by embolization of the left main coronary artery and was evidenced by a significant increase in LV end-diastolic pressure (LVEDP) and decrease in LV dP/dtmax and in cardiac output. Measurements of femoral, renal, mesenteric, and carotid blood flows showed a redistribution of cardiac output during failure. Femoral blood flow decreased to a greater extent than did cardiac output, carotid blood flow decreased in proportion to cardiac output, whereas mesenteric and renal blood flows were moderately reduced in relation to the decrease in cardiac output. Administration of 0.125 mg of propranolol intravenously (i.v.) significantly decreased the performance of the failing left ventricle. Reductions in cardiac output were accompanied by reductions in the peripheral circulations. The decrease in flow was evenly distributed in the femoral, mesenteric, and carotid vascular beds, while there was a relative preservation of renal blood flow. When the dose of propranolol was increased to 0.5 mg/kg, there were no further significant hemodynamic alterations.

Distribution of the increased cardiac output secondary to the vasodilating and inotropic effects of secretin

Infusion of the peptide secretin augments cardiac output due to vasodilating and inotropic properties. The aim of this investigation was to study how the increased cardiac output is distributed in the peripheral circulation. Before, during and after 15 min infusion of secretin 64 CU kg-1 h-1 flow changes in renal, carotid, femoral and the superior mesenteric arteries were measured by means of electromagnetic flowmetry in anaesthetized dogs. Cardiac output and stroke volume increased by 41 and 27%, respectively, whereas the total systemic resistance fell 35%. The LVdP/dt increased by 35%. After 5 min infusion, renal and carotid flows increased by 62 and 50%, respectively, whereas the femoral flow was only slightly elevated and the superior mesenteric flow unchanged. Both the femoral and the superior mesenteric flow gradually augmented and at the end of the infusion flow was substantially elevated in all four arteries. The study demonstrated that the increased cardiac output by secretin was distributed to all the four arteries, although a preponderance of flow to the renal circulation was indicated. This flow profile may be regarded as favourable in the management of low output conditions.

Secretin infusion in acute ischemic left ventricular failure: effects on myocardial performance and metabolism in a closed-chest dog model

Acute ischemic left ventricular (LV) failure in eight closed-chest, anesthetized dogs was induced by embolization of the left coronary artery with 50 micron polystyrene microspheres until LV end-diastolic pressure reached 25.2 +/- 1.4 mm Hg. Cardiac output was reduced by 33%, LVdP/dt by 32% and mean arterial pressure fell substantially. Plasma secretin increased significantly during the induction of failure. Infusion of secretin, 16 clinical units X kg-1 X hr-1 caused a persistent increment in LV performance, due to arteriolar dilation as well as a modest inotropic effect. Heart rate was elevated slightly and LV end-diastolic pressure unchanged. Mean arterial pressure was unchanged initially, but decreased slightly at the end of the infusion period. Myocardial oxygen consumption was unaltered. It is concluded that secretin may be well suited for the treatment of acute LV failure.

Effects of high doses of insulin on regional blood flows during acute left ventricular failure in dogs

This study describes the effects of high doses of insulin on systemic haemodynamics and regional blood flows during acute ischaemic heart failure in dogs. Left ventricular (LV) dysfunction was induced by embolization of the left main coronary artery, and was evidenced by a significant increase in LV end-diastolic pressure and decrease in LVdP/dtmax and cardiac output. Measurements of femoral, renal, mesenteric and carotid blood flows showed a redistribution of cardiac output during failure. Femoral blood flow decreased to a greater extent than cardiac output, but carotid blood flow decreased in proportion to cardiac output, while mesenteric and renal blood flows were moderately reduced in relation to the decrease in cardiac output. Administration of 300 IU of fast-acting insulin significantly improved the performance of the failing left ventricle. Cardiac output was raised to levels observed before failure. The greatest increases in peripheral flow occurred in the femoral and carotid vascular beds, while the least occurred in the mesenteric and renal vascular beds. These observations indicate that insulin at high dose levels significantly improves peripheral circulation by positive inotropic and vasodilatating effects. There was a tendency to favour femoral and carotid vascular flows, but not at the expense of renal and visceral flows. Beta receptor blockade blocked neither the systemic nor regional haemodynamic effects of insulin.

Renal blood flow during acute ischaemic heart failure in dogs: effects of dopamine and high doses of insulin

The effects of acute ischaemic heart failure on renal blood flow and the influence of dopamine at low dose range and high doses of insulin were examined. Acute left ventricular (LV) failure was induced in dogs by injection of 50-micron plastic microspheres into the left main coronary artery. The dogs showed signs of severely depressed LV function. Cardiac output was decreased to a significantly greater extent than renal blood flow, and while total peripheral resistance was significantly increased, there were no significant changes in renal vascular resistance. The results indicate different sympathetic discharge to the various vascular beds during acute ischaemic heart failure. Dopamine at low dose range and high doses of insulin were found to improve myocardial contractility and to reduce renal vascular resistance and increase renal blood flow.

Total body oxygen consumption and haemodynamics during the treatment of acute ischaemic heart failure with dopamine and high doses of insulin in dogs

Acute ischaemic left ventricular failure was induced in closed-chest anaesthetized dogs by injection of 50 microns plastic microspheres into the left main coronary artery. This effected a 33% decrease in cardiac output. Dopamine and high doses of insulin restored cardiac output, and these agents in combination raised cardiac output to 34% above pre-ischaemic levels. Total body oxygen consumption was calculated at the various levels of cardiac output, and was found to remain essentially unchanged. Inotropic agents, then, may result in overperfusion with respect to oxygen demand.

Effects of high doses of insulin on systemic haemodynamics and regional blood flows in dogs

This study describes the effects of a wide range of plasma concentrations of insulin on systemic haemodynamics and free fatty acids (FFA) and the effect of a high dose of insulin on regional blood flows in the femoral, carotid, mesenteric and renal arteries. Insulin was infused in 10 dogs at rates of 4, 8, 16, 32, 64 and 128 IU/kg/h, and the experiments were concluded with a bolus injection of 300 IU. Plasma glucose concentrations were kept constant during the experiments. A dose-related increase in maximum rate of left ventricular pressure rise, stroke volume and cardiac output, and decrease in total peripheral resistance was found with insulin infusion rates up to 64 IU/kg/h. Heart rate and mean aortic blood-pressure were unchanged. The maximum antilipolytic effect was obtained at an infusion rate of 16 IU/kg/h. Insulin was given as a bolus dose of 300 IU in 6 dogs. Blood-flow was increased in all vascular beds, but insulin caused a redistribution of cardiac output. The greatest increases occurred in the femoral and carotid vascular beds, and the least occurred in the renal bed. Mesenteric blood-flow was increased in proportion to cardiac output. The results suggest that insulin exerts combined positive inotropic and vasodilating effects at high dose levels, which result in improved regional perfusion. It may be a potentially useful clinical agent with special benefit under circumstances where enhanced cerebral blood-flow is of importance.

Haemodynamic effects of insulin and beta receptor blockade during acute left ventricular failure in dogs

Acute ischaemic heart failure was induced in 13 dogs by coronary embolisation. Severe dysfunction of the left ventricular (LV) performance was shown by a significant increase in LV end-diastolic pressure and significant decreases in maximum rate of LV pressure rise (LVdP/dtmax), stroke volume and cardiac output. 300 IU of fast-acting insulin was injected as a bolus dose in 7 dogs 90 min after the embolisation procedure. This was followed by infusion of glucose and potassium to maintain normal blood levels. After 15 min, insulin had significantly improved the performance of the failing left ventricle. Total peripheral resistance was decreased. Myocardial blood flow was significantly increased while myocardial oxygen consumption was unchanged. After beta receptor blockade with propranolol 0.5 mg kg-1 given intravenously, the improvement in cardiac performance was reduced, heart rate decreased, and a concomitant decrease in myocardial blood flow and oxygen consumption was recorded. Compared with values before treatment, the net effect of combined insulin and beta receptor blockade was unchanged LVdP/dtmax, LV end-diastolic pressure and cardiac output, significantly increased stroke volume and decreased heart rate, and moderately reduced total peripheral resistance and mean aortic blood pressure. Myocardial blood flow was unaltered, while myocardial oxygen consumption was significantly reduced. In the control group of 6 dogs propranolol was given before insulin, and similar haemodynamic alterations were found.

Haemodynamic effects of pharmacological doses of secretin in patients with impaired left ventricular function

The haemodynamic effects of secretin 4 CU/kg.h was studied in seven patients with impaired left ventricular function. Cardiac output (P less than 0.01) and stroke volume (P less than 0.05) increased persistently during the infusion period, whereas the total systemic resistance fell (P less than 0.01). Heart rate increased slightly (P less than 0.01). The systemic arterial pressure was unchanged except for a small, transient reduction at the onset of the infusion (P less than 0.01). The pulmonary capillary wedge pressure, the pulmonary artery pressure and the pulmonary arteriolar resistance were unaltered. In patients with depressed cardiac function, pharmacological doses of secretin increased left ventricular performance by means of arteriolar dilation and a positive inotropic effect is also suggested.

Metabolic effects of low and high doses of insulin during beta-receptor blockade in dogs

Metabolic effects of low and high doses of insulin during beta-receptor blockade were studied in eight dogs. Beta-receptor blockade was induced by 0.5 mg/kg propranolol which caused depression of heart performance. This was accompanied by a significant reduction in myocardial blood-flow and oxygen consumption. There was also a significant reduction in arterial concentrations and myocardial uptake of free fatty acids, while arterial concentrations and myocardial uptake of glucose and lactate were not significantly changed. Fifteen minutes after beta receptor blockade, an intravenous (i.v.) bolus injection of 0.5 IU/kg, of insulin, free of glucagon and calcium, was given followed by a continuous infusion of 0.5 IU/kg/h. Glucose and potassium were given to maintain constant levels of these factors. After 30 min another bolus dose of 300 IU insulin was injected. Thirty minutes after a low dose of insulin, a significant increase in heart performance was recorded at unaltered myocardial oxygen consumption. Arterial concentrations of free fatty acids were significantly reduced while levels of glucose and lactate were unchanged. Myocardial uptake of glucose increased significantly while uptake of lactate and free fatty acids was unchanged. After a high dose of insulin there was a considerable improvement in heart performance. Myocardial blood-flow and oxygen consumption were not changed, nor were there alterations in arterial concentrations and myocardial uptake of glucose, lactate and free fatty acids. It is concluded that, during beta-receptor blockade high doses of insulin improve the mechanical performance of the heart through mechanisms that are independent of insulin's effects on substrate metabolism.

Haemodynamic effects of low and high doses of insulin during beta receptor blockade in dogs

Haemodynamic effects of small and high doses of insulin during beta receptor blockade were studied in nine dogs. Beta receptor blockade was induced by 0.5 mg/kg propranolol and caused depression of cardiac performance with a significant increase in left ventricular end-diastolic pressure (LVEDP) and a significant decrease in heart rate; maximum rate of left ventricular (LV) pressure rise (LVdP/dtmax), stroke volume and cardiac output. At 15 min, after beta receptor blockade, a bolus injection of 0.5 IU/kg of insulin, free of glucagon and calcium, was given followed by a continuous infusion of 0.5 IU/kg/h. After 30 min another bolus dose of 300 IU insulin was injected. Glucose and potassium were given to maintain physiological levels of these factors. Five minutes after a low dose of insulin there was a significant decrease in LVEDP (P less than 0.01), and a significant increase in LVdP/dtmax (P less than 0.01), in stroke volume (P less than 0.01) and in cardiac output (P less than 0.01). The other haemodynamic variables were not significantly changed. Administration of a high dose of insulin further, significantly, improved performance of the beta receptor blocked heart and caused a significant reduction in total peripheral resistance. In conclusion, insulin exerts inotropic and vasodilator effects which are dose-dependent and not related to adrenergic mechanisms.

Haemodynamic effects of high doses of insulin during acute left ventricular failure in dogs

Haemodynamic effects of pharmacological doses of insulin during acute ischaemic heart failure were studied in 8 dogs. Severe depression of left ventricular function was induced by the injection of 50 micron plastic microspheres into the left main coronary artery. This was demonstrated by a significant increase in left ventricular end-diastolic pressure and a significant decrease in the maximum rate of left ventricular pressure rise (LVdP/dtmax), stroke volume and cardiac output. Eighty-five minutes after the embolization procedure, 300 IU of insulin free of glucagon and calcium was injected as a bolus. This was followed by infusion of glucose and potassium to maintain physiological levels of these factors. Five minutes after insulin administration, there was a significant improvement in left ventricular performance as shown by decreased left ventricular end-diastolic pressure (P less than 0.01) and increased LVdP/dtmax (P less than 0.01), stroke volume (P less than 0.05) and cardiac output (P less than 0.05). A significant reduction in heart rate occurred. A non-significant increase in mean aortic blood pressure and reduction in total peripheral resistance were seen. In conclusion, pharmacological doses of insulin significantly improve cardiac pump function during acute ischaemic left ventricular failure in dogs.

Metabolic effects of high doses of insulin during acute left ventricular failure in dogs

Metabolic effects of pharmacological doses of insulin were studied during acute ischaemic heart failure in 7 dogs. Severe depression of left ventricular performance was induced by embolization of the left main coronary artery with 50 micron plastic microspheres. This was followed by a significant reduction in myocardial blood flow and oxygen consumption. After a period of stabilization of the haemodynamic and metabolic variables, 300 IU of insulin free of glucagon and calcium was injected as a bolus dose. Glucose and potassium were given to maintain their plasma concentrations. Insulin significantly improved performance of the failing left ventricle. Myocardial blood flow was significantly increased, whereas myocardial oxygen consumption was unchanged. Insulin significantly reduced arterial concentrations and myocardial uptake of free fatty acids, while myocardial uptake of glucose and lactate showed a non-significant increase. In conclusion, pharmacological doses of insulin significantly improve cardiac pump function without increasing myocardial oxygen consumption during acute ischaemic left ventricular failure in dogs. This may be partly related to reduced myocardial uptake of free fatty acids relative to that of glucose.

Cardiovascular effects of secretin infusion in man

Secretin infusion in man causes an increase in renal blood flow. The aim of the present study was to assess further the cardiovascular effects of the hormone. Secretin was infused at a rate of 2 CU/kg X h to patients with angina pectoris and normal left ventricular function. Cardiac output increased by an average of 20%, the stroke volume increased and the total systemic resistance decreased. Systemic arterial pressure, heart rate and pulmonary capillary wedge pressure were unaltered. The results are compatible with a combined inotropic and vasodilating effect of the hormone. It is concluded that secretin may have potential merits in the treatment of acute left ventricular failure.

Multilevel disease of the conduction system

We found that the incidence and distribution of conduction system disease simultaneously affecting several levels of the system had been incompletely described. We therefore analysed all patients in whom conduction disease had been diagnosed and a complete electrophysiological study of the conduction system had been made, during a defined period. Patients were classified as to the presence or absence of sinus node disease, and proximal and distal atrioventricular disease. Since our hospital serves a defined population and a large proportion of all patients with conduction disease seen during the period was included, the series probably is representative of conduction disease in general. Twenty-four of the 59 patients had defects at more than one of the three levels (41%). Fifty-five per cent of the patients with sinus node disease had some kind of atrioventricular disease, while 42% of the latter had evidence of sinus node failure. The patients with multilevel disease were characterized by more severe symptoms, higher age and a higher incidence of generalized heart disease than those with single-level disease. The observations fit the concept that conduction system disease in most patients is part of a diffuse disease process progressively involving various parts of the system.

Renal excretion of and the effect of posture on serum group I pepsinogens

Serum group I pepsinogens (PG I) were determined by a radioimmunoassay method in blood drawn from the right femoral vein, the right renal vein, the liver vein, the right atrium, and the left femoral artery from 10 patients undergoing cardiac catheterization. Clinically they had no cardiac insufficiency, and their renal function was normal. The serum PG I concentration was similar in the femoral artery and vein and in the right atrium. On the other hand, serum PG I was higher in the liver vein and lower in the renal vein than in the other sampling sites. The renal arteriovenous serum PG I difference was positively correlated to the arterial concentration. The influence of posture on serum PG I was studied in another nine healthy subjects. Serum PG I was lower in the supine position than in the erect position.

Removal of IR-GIP by the kidneys in man, and the effect of acute nephrectomy on plasma GIP in rats

In a group of 10 patients undergoing routine cardiac catheterization, mean plasma gastric inhibitory polypeptide (GIP) was significantly lower (p = 0.002) in blood drawn from the renal vein than in blood drawn from the hepatic vein, the right atrium, the femoral vein, and the femoral artery, demonstrating the removal of immunoreactive GIP by the kidneys. In a group of eight nephrectomized rats, mean plasma GIP was significantly higher 30 and 60 min after start of intraduodenal glucose infusion (p = 0.03 and p = 0.002, respectively) as compared with eight control rats, which probably reflects reduced removal of GIP in the nephrectomized group.