Endovascular treatment of a pulmonary artery pseudoaneurysm caused by Swan-Ganz catheter deployment in an anticoagulated patient

We present a case report of an anticoagulated 78-year old man presenting a pulmonary artery pseudoaneurysm following Swan-Ganz catheter deployment after an aortic valve and aortic root replacement. Diagnosis was established by cone beam CT angiography and catheter angiographyand embolisation was achieved via a combination of plug and glue. This case emphasises the importance of endovascular techniques in the management of iatrogenic pulmonary pseudoaneurysms and shows the benefit of using highly hemostatic polymeric agent in anticoagulated patients to obtain a rapid and effective occlusion.

MRI evaluation of myocardial viability

Cardiac magnetic resonance imaging (MRI) has become an accurate noninvasive imaging procedure for the study of postischaemic residual cardiac function, thanks to the evolution of MRI machines, postprocessing software and, above all, sequences. After infarction, and in chronic myocardial ischaemia, the degree of contractile dysfunction is one of the main determinants of longterm survival. The identification and quantification of viable dysfunctional myocardium and the possibility of improving its contractility after revascularisation improves patient prognosis and quality of life. In current clinical practice, myocardial viability is evaluated with stress echocardiography and nuclear methods. Thanks to its intrinsic characteristics and to the delayed-enhancement technique (DE-MRI), MRI has recently emerged as the only noninvasive modality able to provide a three-dimensional (3D) evaluation of cardiac viability with a multiparametric approach.

Imaging of post-traumatic cardiac rhabdomyolysis with normal coronary arteries

Numerous cases of acute myocardial infarction (AMI) have been reported in the literature following closed chest injuries, due to post-traumatic dissection or thrombosis of a coronary artery. In the follow-up of AMI, wall thickness during diastole and systole provides important information on heart viability. Multidetector computed tomography (MDCT) is currently the only noninvasive instrumental investigation which provides an appreciable assessment of the coronary arteries, as well as heart wall thickness measurements. We describe and discuss the clinical and imaging findings, especially of MDCT, in a case of post-traumatic regional myocardial necrosis with normal coronary arteries.

Primary cardiac Burkett's type lymphoma: transthoracic echocardiography, multidetector computed tomography and magnetic resonance findings

Although primary cardiac lymphoma is an extremely rare disease and is associated with high mortality, it is treatable when diagnosed appropriately. We describe the transthoracic echocardiography, 16-row multidetector computed tomography (16-MDCT) and magnetic resonance findings of primary cardiac lymphoma in an immunocompromised patient and review of the literature.

Acute changes in circulating hormones in older patients with impaired ventricular function undergoing on-pump coronary artery bypass grafting

OBJECTIVES

Coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) causes an acute stress response characterized by changes in the levels of several hormones, which might play a role in the high complication rate experienced by older patients after CABG. Thus, the aim of the study was to investigate changes in the circulating levels of anabolic and catabolic hormones in old people undergoing CABG with CPB.

DESIGN

Intervention case study.

METHODS

19 patients (12 males, 7 females) aged 70.1 +/- 6.1 yr (age range 62-80) with coronary artery disease and an ejection fraction <40% who underwent cardiac surgery. Cortisol (Cort), DHEA, DHEAS, LH, estradiol (E2), total testosterone (Te), SHBG, IGF-I were measured the day before, on the day of the procedure and 1, 2, 3, 4, and 30 days after CABG.

RESULTS

After surgery, serum IGF-I levels decreased (p<0.001), while levels of Cort, DHEAS and E2 significantly increased in both men and women. Alterations in Te levels differed between the two sexes with a significant decline in men and a significant increment in women.

CONCLUSION

CABG with CPB resulted in a dramatic drop in Te levels in old men and a significant decline in IGF-I in both sexes. Serum Cort levels also significantly increased in both sexes. These hormonal changes may, at least partially, explain why the elderly need prolonged rehabilitation after CABG.

Neurologic symptoms after great saphenous vein harvesting for coronary artery bypass grafting

AIM

Incidence evaluation of cutaneous neurologic symptoms in the lower limbs as a new event after great saphenous vein (GSV) harvesting for coronary artery bypass grafting (CABG). Each day we harvest the GSV for CABG. Some authors have reported the onset of saphenous neuralgia complex as a new event of which we would evaluate the incidence.

METHODS

From January 2000, until June 2001, 2,091 patients underwent cardiac surgery; 1,326 underwent CABG, 1,227 of them using the GSV as a conduit for almost one graft. These patients were prospectively reviewed; all were preoperatively examined to determine the presence of normal sensation in the lower limbs and elude the presence of saphenous neuralgia. Then, we evaluated sensations in the lower limbs at 5 days, 8 weeks, and 5 months after operation to determine the new onset of saphenous neuralgia. The areas of sensory loss were recorded each time and reported in a diagram to obtain 3 areas.

RESULTS

Hyperaesthesia and pain were noted in a few patients, especially at 5 days and 8 weeks control, but at 5 months none of them complained of real pain.

CONCLUSION

This study demonstrates that saphenous neuralgia after harvesting the GSV for CABG is a rare consequence. The main symptom is anaesthesia but its duration is generally no longer than 2 months. Hyperaesthesia and pain, for the early onset and the early disappearance, are considered as a normal consequence of surgical procedure.

Thoracic aortic stents: a combined solution for complex cases

OBJECTIVES

The combination of endovascular and standard surgical techniques may facilitate the management of complex aortic disease although the long-term durability of this approach needs to be confirmed.

DESIGN

A retrospective review of our experience in the treatment of patients with complex aortic pathology using a combined endovascular and surgical approach.

MATERIALS AND METHODS

Between 1998 and 2001, 27 patients with thoracic aortic aneurysm underwent stent-graft implantation. Eight required combined endovascular and surgical procedure because of complex pathology. In 3 cases, combined repair was carried out for a concomitant abdominal aortic aneurysm or aorto-iliac-femoral occlusive disease. In the other 5 cases, vessel relocation was performed to obtain safe landing zones: left subclavian artery to left carotid artery translocation in 3 patients, celiac trunk to superior mesenteric artery translocation in one and aorto-celiac-mesenteric bypass grafting in one.

RESULTS

One of the 8 patients died on 12th post-operative day of intestinal bleeding and bowel infarction. No neurological sequelae were reported. The other patients are currently well at 11 months mean follow-up time.

CONCLUSIONS

Simultaneous surgical and endovascular procedure is a feasible and may be a valuable adjunct to the treatment of complex aortic and peripheral vessel anatomy.

Pericardial drainage for pericardial tamponade: surgical management criteria

Aim of this study is the review of our experience in 82 patients treated by pericardial drainage for cardiac tamponade, to assess the efficacy and safety of different techniques and the related indications. The causes of pericardial effusion were: malignancy in 8 patients (9.7%), post-cardiac surgery in 12 (14.6%), while the others patients were admitted at our Institution with no identified preoperative diagnosis. Thirty-eight patients (46%) underwent subxiphoid pericardial drainage and 44 (54%) were operated on by catheter pericardiocentesis. There were no perioperative deaths. Two patients, who initially underwent pericardiocentesis, needed urgent sternotomy: the first patient developed a severe hypotension and bradicardia related to a vagal reaction and the other one because of accidental right ventricle puncture. Our experience indicates that subxiphoid pericardiocentesis provides expeditious, effective and durable treatment, with low morbidity, in case of pericardial effusions related to all causes. We believe that echocardiography is a powerful tool in the diagnosis and management of pericardial effusion. We conclude that pericardiocentesis seems to be the procedure of choice for patients with pericardial tamponade requiring an emergency treatment.

Ischaemic mitral valve regurgitation: a surgical approach

The aim of this study IS to determine surgical results after surgical mitral valve repair in ischaemic mitral regurgitation.

MATERIALS AND METHODS

Between January 1999 and June 2000, 64 patients (5.1% of overall patients) underwent myocardial revascularization and mitral valve surgery. A Cosgrove-Edwards mitral annuloplasty ring was used in 59 cases (92.2%). Average patient age was 64.3 +/- 12.4 years (38 males, 21 females). Average degree of mitral regurgitation was 2.8 +/- 0.6. Average NYHA class was 3.5 +/- 0.5. Average ejection fraction (EF) was 40 +/- 12.5 percent.

RESULTS

Post-operative 30-day mortality was 3.4% (2 patients). The follow-up was complete for 95 percent (mean 20.4 +/- 4.8 months for patients) and data showed an improvement of NYHA class (mean value 1.8 +/- 0.2) (p = 0.01) and ejection fraction (mean value 51.7 +/- 10.2) (p = 0.05) with residual mitral regurgitation value of 0.6 +/- 0.7.

CONCLUSIONS

Mitral valve repair in coronary artery disease improves left ventricular function, quality of life and survival rate with low operative risk. Perioperative transesophageal echocardiography has a central role in surgical decision making.

Surgical repair of thoracic aortic aneurysms: results and complications

Between January 1990 and February 2001 a total of 323 patients underwent following operations at our Institution: respectively 256 on the ascending aorta, 13 on the transverse arch and 54 on thoracic descending aorta. Sixteen patients with thoracic aortic aneurysms underwent endovascular stent graft implantation. The overall in-hospital mortality was respectively: 7% for ascending aortic aneurysms, 7.7% in the aortic arch aneurysms group and 5.5% for descending aortic aneurysms. The mortality was greater in case of emergency surgery and in the subgroup of patients with acute type A dissection. Stroke with permanent dysfunction occurred in 1.5% of ascending aneurysms, 7.7% of arch aneurysms and in 3.7% of thoracic descending aneurysms. In the latter group, all the major neurological events were related to conventional surgical procedures only: really no mortality or neurological morbidity occurred with endovascular stent graft implantation. Even if modern physiologic monitoring devices and new surgical techniques have been developed in the last years, the treatment of thoracic aortic aneurysms remains challenging. Endoluminal placement of stent grafts has developed as an alternative procedure for the treatment of thoracic aortic aneurysms, even if longer term follow-up is still necessary to fully define the efficacy of this approach.

[Endoluminal repair of aortic aneurysms. Our experience]

From February 1998 and March 2000 fourteen patients underwent "custom made" aortic self-expanding endoprostheses implantation (World Medical Talent Sunrise): nine of them for dilative pathology of thoracic aorta and 5 for abdominal aortic aneurysm below renal arteries. The etiology was degenerative in 8 patients, false aneurysm in 2, chronic dissection in 2 cases, acute dissection in one patient and post traumatic in the last one. All patients underwent preoperative Computed Tomography and Substraction Angiography studies. Stent-graft implantation was successful in all cases but one who required the conversion of the endovascular procedure in traditional surgery for technical problems. There were no perioperative deaths or major complications. We registered 2 cases of dissection of the femoral artery used to introduce the stent-graft, and treated with an iliac-femoral prosthetic bypass. There were no cases of paraplegia or renal failure or bowel ischemia. With the exception of one patient, died for a car accident, the others are alive and continue their scheduled follow-up controls. Our experience shows that this procedure is safe, allowing favorable results, if compared to traditional surgery, even if it requires further long-term evaluations.

Outbreak of acute renal failure due to cefodizime-vancomycin association in a heart surgery unit

OBJECTIVE

To describe an outbreak of acute renal failure (ARF) occurring in a group of patients undergoing open-heart surgery, simultaneously to a change in perioperative antibiotic prophylaxis.

DESIGN

Case series.

SETTING

A nine-bed heart surgery intensive care unit, serving a 1,300-bed University teaching hospital.

PATIENTS

Thirty-two patients undergoing open-heart surgery during an 11-day period, when the preoperative surgical prophylaxis protocol had been changed from the usual antibiotic association of ceftriaxone + vancomycin to cefodizime + vancomycin.

RESULTS

ARF occurred in 16 of the 32 (50%) patients exposed to the new antibiotic prophylaxis regimen; seven patients had oliguric ARF, and nine patients had an increase in serum creatinine (SCr) levels >50% over 24-48 h. In the seven patients with oliguric ARF, SCr increased from a median preoperative level of 88 micromol/l (80-115 micromol/l) to a peak value of 725 micromol/l (521-857 micromol/l) in 5 days (4-6). Eight patients out of the sixteen with ARF (50%) were diabetics, as opposed to none of the 16 patients not experiencing ARF. Renal biopsy (three patients) showed tubular dilation and necrosis, interstitial edema, and lymphomononuclear infiltrate of moderate degree. Only one patient required hemodialysis, and all recovered renal function. No other cases of unexplained ARF occurred in the unit after the original prophylaxis protocol was resumed.

CONCLUSION

The simultaneous infusion of cefodizime and vancomycin may involve a high risk of substantial renal function derangement, especially in diabetics.

[Total arterial myocardial revascularization: surgical technique and mid-term results]

The purpose of this study is to evaluate perioperative and mid-term results of total arterial coronary revascularization in our experience and to establish its safety. One-hundred and ninety-one patients underwent total arterial coronary revascularization at our Institution from February 1997 to August 2000. The mean age was 60.1 years. Of the patients, 45% had three coronary vessels disease, 12% a left main coronary artery disease and 2.6% of them were classified urgent. Mean ejection fraction was 59.6%. Three hundred and thirty-four comprehensive anastomoses were performed; mean grafts per patient was 1.8. A Y or T graft with the left internal thoracic artery was used in 21 patients. The in-hospital mortality rate was 1% (2 patients). Complications included low cardiac output syndrome in 2.8% of patients, acute myocardial infarction in 0.9% and acute renal insufficiency in 3.1%. Intraaortic balloon pump was used in 1.8% of patients. At a mean follow-up of 899 days the first 81 patients contacted are all free of angina but two (one experienced an acute myocardial infarction and another one died for a pulmonary neoplasia). We conclude that total arterial coronary revascularization is a safe surgical technique, providing excellent perioperative and mid-term results.

Hemodynamic, respiratory, and metabolic effects of medium-chain triglyceride-enriched lipid emulsions following valvular heart surgery

STUDY

A lipid emulsion containing 10 percent medium-chain triglycerides (MCT) and 10 percent long-chain triglycerides (LCT) was infused at a rate of 1 ml/kg/h (3.3 mg/kg/min) for 2 h, in 12 patients (2 males, 10 females; mean age, 54 +/- 3 (SEM) years; range, 34 to 67 years) 24 h after open-heart surgery (mitral valve replacement).

METHODS

Hemodynamic factors (pulmonary and radial artery indwelling catheters), oxygen and carbon dioxide partial pressures, oxygen saturation, oxygen delivery and consumption, and intrapulmonary shunt fraction were obtained before, during, and after lipid infusion (for 2 h), at 30-s intervals, along with some metabolic indexes (triglycerides, free fatty acids, glucose, insulin, lactate, acetoacetate).

RESULTS

No statistically significant changes in heart rate, cardiac index, systemic and pulmonary pressures and resistances, central venous and pulmonary capillary pressures, or arterial oxygen partial pressure were observed during infusion. Arterial carbon dioxide partial pressure values were constantly reduced throughout and after the end of lipid infusion, as compared with baseline values, while oxygen consumption was increased significantly without any change in oxygen delivery. No adverse effects on intrapulmonary shunt fraction were observed. Statistically significant increases of triglycerides, free fatty acids, acetoacetate and insulin (peak values at end of the lipid infusion) were found in comparison with baseline values. Plasma glucose increased significantly during lipid infusion and remained higher than baseline values until the end of the study. Lactate levels were unchanged except for a slight decrease at the end of the study, without any derangement of acid-base equilibrium. Neither arrhythmias nor adverse clinical reactions were observed as a consequence of lipid infusion.

CONCLUSIONS

Fat emulsions containing both MCT and LCT, when given at 3.3 mg/kg/min for 120 min following valvular heart surgery, do not exert negative cardiopulmonary effects, and could represent a source of rapidly metabolized substrates.

Prevention of deep venous thrombosis by a new low molecular weight heparin (Fluxum) in cardiac surgery

The prophylactic deep venous antithrombotic efficacy of a low molecular weight heparin (LMWH) was compared with traditional unfractionated calcium heparin in 39 patients submitted to cardiac surgery. The patients were allocated at random to receive either LMWH-Fluxum 3200 IUaXa daily (Group A: 20 patients) or calcium heparin 5000 IU three times daily (Group B: 19 patients). Both treatments were started on the first day after surgery and continued over the fourth postoperative days. One or more risk factors for deep venous thrombosis in addition to the cardiac pathology were present in all the patients of group A and in 13 (72.2%) of group B. Mean times of surgery, blood loss during the perioperative period and number of blood units transfused in both groups were not statistically significant. The deep venous system was investigated by continuous wave Doppler and real time colour Echotomography. No evidence of thrombosis was detected in the two groups. Side effects and subcutaneous hematomas were present in only four patients of group B. Both drugs showed good tolerance, provoking no variations of the main laboratory parameters. We conclude that Fluxum (LMWH) for the efficacy and convenience given by a single daily dose, could represent an alternative choice in the prevention of deep venous thrombosis in cardiac surgery.

[Thallium-201 myocardial perfusion imaging after aortocoronary bypass in patients treated with sulodexide or ASA-dipyridamole]

The aim of this investigation was to compare the preventive effect of sulodexide, a glycosaminoglycan drug, tested versus ASA-dipyridamole association, on the occlusion of venous aortocoronary bypass. A group A of 23 patients, for a total of 22 anastomosis with internal mammary artery and 46 venous bypass, was treated with sulodexide 500 USL/day. A group B of 18 patients for a total of 19 anastomosis with internal mammary artery and 33 venous bypass, was treated with ASA-dipyridamole 300 mg + 400 mg/day. Three and 9 months after surgery, all patients underwent thallium-201 myocardial perfusion imaging, associated with ergometric test. At the first control after 3 months, reversible perfusion defect in one or more myocardial segments was observed in 8 patients of group A and 3 patients of group B (2 A patients and 1 B patient in non revascularized myocardial segments); after 9 months, reversible perfusion defects were observed in 4 A patients and in 4 B patients. After 3 months, non reversible perfusion defect imaging in non infarcted myocardial segments was observed in 2 A patients and in 1 B patient; after 9 months, in 1 patient of both groups. This research shows higher incidence, at first control after 3 months, of ischemic reversible perfusion defects in patients treated with sulodexide, with an evident improvement in some patients recontrolled after 9 months. At the last control after 9 months, the scintigraphic findings showed similar evidence of perfusion defects in both groups treated with sulodexide or ASA-dipyridamole, with concordant angiographic findings (78.6%). Our preliminary results are encouraging and suggest further widespread studies on sulodexide therapy.

Carotid endarterectomy under hypothermic extracorporeal circulation: a method of brain protection for special patients

This study was undertaken to evaluate the efficacy of hypothermic extracorporeal circulation for cerebral protection in 17 patients having simultaneous carotid endarterectomy and cardiac operations. The cardiopulmonary by-pass (CPB) was conducted using total hemodilution. The body temperature was cooled to 25 degrees C and the heart was arrested with cardioplegic solution. The carotid endarterectomy was performed first followed by the cardiac operation. No neurological or cardiac complications occurred. These results support the reliability of hypothermic cardiopulmonary bypass as a method of providing cerebral protection during simultaneous cardiac and carotid surgical procedures.

A comparative clinical study on the effects of cardiopulmonary bypass with different flows and pressures on skeletal muscle cell metabolism in patients undergoing coronary bypass grafting

This study compares the effects of cardiopulmonary bypass with different flows and pressures on intracellular energy metabolism, acid-base equilibrium, and muscle water compartments in two groups of patients undergoing coronary artery bypass grafting. Eighteen patients (16 men and two women aged 54 +/- 7 years, New York Heart Association class I-II) undergoing low flow (flow rate 1.5 L/min/m2 at 26 degrees C), low pressure (mean arterial pressure 40 to 60 mm Hg) cardiopulmonary bypass, as well as 10 age-matched and sex-matched patients undergoing normal flow (flow rate 2.2 L/min/m2 at 26 degrees C), normal pressure (mean arterial pressure 60 to 80 mm Hg) bypass were studied. Intracellular acid-base equilibrium (intracellular pH and intracellular bicarbonate), cell energetics (adenosine triphosphate, diphosphate, and monophosphate, phosphocreatine, and lactate), and muscle water compartments were evaluated in specimens of the quadriceps femoris muscle obtained by needle biopsy before and at the end of cardiopulmonary bypass. In both the low flow-low pressure and normal flow-normal pressure groups, adenosine triphosphate levels were unchanged at the end of bypass, whereas phosphocreatine concentration was decreased; muscle total water and extracellular water increased without variations of intracellular water; muscle and plasma lactate increased as intracellular bicarbonate decreased; intracellular pH values remained unchanged. The present study suggests the following: (1) Cardiopulmonary bypass is associated with the overall preservation of intracellular compartment metabolism in skeletal muscle (about 40% of body cell mass) of patients undergoing coronary bypass grafting, even though low phosphocreatine values and increased plasma and muscle lactate values found at the end of bypass could be an expression of cell functional reserve exhaustion; (2) the effects of cardiopulmonary bypass on cell metabolism are comparable, regardless of the flows and pressures used.

Cell metabolism in patients undergoing major valvular heart surgery: relationship with intra and postoperative hemodynamics, oxygen transport, and oxygen utilization patterns

The relationships between cell metabolism and both hemodynamics and oxygen transport/utilization (VO2/DO2) pattern were evaluated intra and postoperatively in eight patients undergoing major valvular heart surgery with the aid of moderately hypothermic cardiopulmonary bypass (CPB). Quadriceps femoris specimens were obtained by the needle biopsy technique for muscle ATP, ADP, AMP, phosphocreatine (PCr), creatine and lactate determination at anesthesia induction, after CPB, as well as in the ICU 18 h after surgery. Moreover, hemodynamic variables, oxygen transport and utilization indices, and plasma lactate were measured at the same intervals and throughout the CPB period. After CPB, muscle ATP and PCr contents were reduced (p less than .05) as compared to those of both pre-CPB patients and healthy control subjects; muscle and plasma lactate levels were increased (p less than .05). Mean VO2 and DO2 values measured during CPB significantly decreased (p less than .05), but VO2 reduction was proportionally greater than that of DO2 (-62% vs. -41%). No correlation was found between VO2 and DO2 at that time, but a significant relationship (p less than .05) was found at the end of CPB. A further decrease in muscle ATP and PCr levels was measured in the ICU, as muscle and plasma lactate levels were still elevated. At that time, VO2 and DO2 were not significantly different from pre-CPB values, but were significantly (p less than .05) correlated with each other.(ABSTRACT TRUNCATED AT 250 WORDS)

[Surgical therapy of post-infarct aneurysm of the left ventricle. Immediate and long-term results]

Between January 1982 and December 1986, 62 patients (59 male and 3 female) ranging in age from 37 to 69 years (mean 53) underwent resection of postinfarction left ventricular aneurysm. The indication for operation was angina in 23 cases (37%), congestive heart failure (CHF) in 7 (11.2%), angina and CHF in 29 (46.8%), rupture in 1; 2 patients were low symptomatic. Ventricular arrhythmias were present in 6 (9.7%) cases and previous systemic embolism in 4 (6.4%). Forty-seven (75.8%) patients had lesions of three coronary arteries with involvement of left main coronary artery in 4 cases; 10 (16.1%) had lesions of two vessels [left anterior descending (LAD) and/or right coronary artery]; 4 (6.4%) had only LAD artery involvement, and 1 had no significant coronary artery stenoses. Left ventricular ejection fraction (EF) was less than 0.30 in 22% of cases, between 0.30 and 0.40 in 25.4% and greater than 0.40 in 50%. The location of the aneurysm was anterolateral or apical (83.8%), posterior (14.5%) and lateral (1.6%). Left ventricular aneurysmectomy with myocardial revascularization was performed in 61 patients (bypass/patient = 2.7), with ventricular septoplasty in 20 and concomitant mitral valve replacement in 3 patients. LAD was grafted in 59.6% of anterior aneurysm. Operative mortality (30 days) was 4.8%, the late mortality, with a follow-up between 12 and 72 months (mean 38), was 6.7% and the actuarial 5 year survival rate was 85% (91% without operative mortality). In our experience, despite no evidence of any operative risk factors, no improvement was noted in radionuclide left ventricular ejection fraction in patients undergoing aneurysmectomy with ventricular septoplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Right atrial hemangioma

A case of right atrial hemangioma as a rare tumor of the heart is reported. Because of its single, pedunculated mass, surgical excision of the tumor resulted in the complete treatment. Histologically, it was classified as arteriolar type. The importance of recent non-invasive techniques to diagnose these tumors during life is emphasized.

Asymptomatic patient reoperated on for severe proximal stenosis of circular sequential vein graft

The case is described of a fifty year old man who underwent coronary bypass surgery using the circular sequential vein graft technique. At follow-up study (6 months after operation), despite his asymptomatic status, the effort test revealed antero-lateral myocardial ischemia. A coronary angiography showed a 90% proximal stenosis of the graft at 1.5 cm from the aortic anastomosis. The patient was reoperated on and the circular graft was reconstructed. Despite the severe stenosis this technique of myocardial revascularization has developed intercoronary anastomoses, improving the cardiac contractility and avoiding further clinical complications.

Response of the border zone to myocardial infarction in rats

The response of the surviving myocardium 30 days after coronary artery occlusion was measured morphometrically in the regions bordering and remote from infarcts of different sizes. Mean cell volume per nucleus increased with infarct size in both zones, but the rate of change was greater in the border than in the remote portion of the unaffected myocardium. Capillary numerical density within the uninjured tissue progressively decreased with infarct size leading to an increased diffusion distance for oxygen. Although the magnitude of changes in capillary density was similar in the two regions of the ventricle, the analysis of the individual values in each heart showed that in infarcts comprising more than 11% of the ventricular wall capillary concentration and the path length for oxygen supply to the myocytes were affected more in the border zone than in the myocardium remote from the scar. In conclusion, the border zone participates in the hypertrophic recovery process after infarction, but the inadequate growth of the capillary microvasculature suggests that this region is more susceptible to additional ischemic episodes.

Effects of low flux-low pressure cardiopulmonary bypass on intracellular acid-base and water metabolism

In eight patients undergoing open heart surgery for elective myocardial revascularization, extra-intracellular acid-base and water metabolism parameters were studied before and after cardiopulmonary bypass procedures. All patients presented a different degree of metabolic acidosis related to plasma lactate increase. Intracellular acid-base indexes did not change significantly, though all but one patient showed an intracellular buffers consumption. Both total muscle and extracellular water increased, while intracellular water did not change. It was concluded that low flux-low pressure perfusion CPB was related to a substantial preservation of cell integrity.

Myocardial infarction in rats. Infarct size, myocyte hypertrophy, and capillary growth

To determine the compensatory reserve capacity of the ventricular myocardium following infarction, the left coronary artery in rats was ligated, and the animals were killed 40 days later. Infarcts affecting an average 23% of the left ventricle were characterized by a 27% hypertrophic growth of the remaining myocardium that produced a complete replacement of the necrotic tissue. In contrast, infarcts with an average 50% loss of mass resulted in 83% expansion of the spared myocardium that was inadequate for a complete restoration of ventricular tissue. Myocyte hypertrophy was 26% and 78% in small and large infarcts, respectively. Cellular hypertrophy in both cases involved significant increases in myocyte transverse area and myocyte length. After large infarcts, there was an 18% reduction in capillary surface and a 16% increase in the diffusion distance. Corresponding values for small infarcts were -10% and 9%. These alterations combined with the deficient reconstitution of myocardial mass following large infarcts resulted in 25%, 29%, and 30% deficits in the absolute amounts of capillary lumen, surface, and length per ventricle respectively. Even with small infarcts, a deficit was seen in capillary luminal surface (-16%), and length (-19%). In conclusion, we have demonstrated that cardiac hypertrophy following myocardial infarction is consistent with cellular shape changes characteristic of a combination of concentric and eccentric hypertrophic growth. However, cardiac muscle cells appear to be unable to compensate for the loss of mass induced by a 50% infarct. The inadequate adaptation of the capillary vasculature in the infarcted hearts suggests that the injured ventricle is more vulnerable to additional ischemic episodes.

Effects of strenuous exercise on the quantitative morphology of left ventricular myocardium in the rat

The adaptation of the structural components in the myocardium of the left ventricle to strenuous exercise was studied morphometrically in rats following a treadmill running program. The response of the left ventricle was evaluated separately in the interventricular septum and in the left ventricular free wall. Exercise produced a 24% growth of the septum without altering free wall volume. The hypertrophic expansion of the septum was characterized by a decrease in the volume fraction of capillary lumen in the myocardium (-20%), a reduction in the capillary luminal surface per unit volume of myocytes (-17%) and by an increase in the maximum distance from the capillary wall to the mitochondria of myocytes (9%). Although none of these changes were demonstrable on a statistical basis in the left ventricular free wall, similar results were obtained in the whole left ventricle by combining the data from the septum and free wall. Since the septum constitutes a functional unit with the free wall, it was concluded that the effect of excessive physical activity on the capillary parameters responsible for oxygen availability and diffusion could lead to a local reduction in the oxygenation potential of ventricular myocardium.

Myocardial response to infarction in the rat. Morphometric measurement of infarct size and myocyte cellular hypertrophy

For determination of the effects of myocardial infarction on the recovery potential of muscle mass in the surviving tissue, ligation of the left coronary artery was performed in 3-month-old rats, and the infarcted ventricles were analyzed morphometrically a month after surgery. Comparisons were made with 4-month-old control rats that underwent sham operations and with 3-month-old control rats that were not operated upon for evaluation of the magnitude of infarct size and discrimination of the relative contribution of tissue growth that occurred in the surviving myocardium solely as a result of the change in age, from 3 to 4 months (postoperative tissue growth, or POTG), from the additional growth induced by infarction (hypertrophic growth, or HG). Coronary occlusion induced a 276-cu mm loss of ventricular tissue volume that corresponded to 43% of the total left ventricular mass, 648 cu mm. Over a 30-day period the remaining 372 cu mm of viable tissue expanded by 90% with an overall volume gain of 334 cu mm. This tissue augmentation consisted of 20% POTG, 67 cu mm, and 80% HG, 267 cu mm. Total myocyte volume increased 89%, from 302 cu mm to 571 cu mm, and average myocyte cell volume per nucleus increased 92%, from 16,500 cu mu to 31,600 cu mu. The expansion of the myocyte mass was the result of a 21% POTG and a 79% HG. Corresponding values for the myocyte population were 19% and 81%.

Morphometry of right ventricular hypertrophy induced by myocardial infarction in the rat

The growth response of the right ventricle was studied in rats following ligation of the left coronary artery, which produced infarcts comprising approximately 40% of the left ventricle. A month after surgery the weight of the right ventricle was increased 30%, and this hypertrophic change was characterized by a 17% wall thickening, consistent with the 13% greater diameter of myocytes. Myocardial hypertrophy was accompanied by an inadequate growth of the microvasculature that supports tissue oxygenation. This was seen by relative decreases in capillary luminal volume density (-27%) and capillary luminal surface density (-21%) and by an increase in the average maximum distance from the capillary wall to the mitochondria of myocytes (19%). In contrast, measurements of the mean myocyte volume per nucleus showed a proportional enlargement of these cells (32%), from 16,300 cu mu in control animals to 21,500 cu mu in experimental rats. Quantitative analysis of the right coronary artery revealed a 33% increase in its luminal area, commensurate with the magnitude of ventricular hypertrophy.

Morphometry of right and left ventricular myocardium after strenuous exercise in preconditioned rats

Young male rats were exposed to a biphasic training program in which a 7-week preconditioning period of moderate treadmill exercise was followed by 8 weeks of strenuous endurance running. In comparison with sedentary control animals, the trained rats at 20 weeks of age had developed myocardial hypertrophy of the right ventricle (20%) and interventricular septum (23%), but there was no difference in the weight of the left ventricular free wall. Myocyte hypertrophy (26%) in the right ventricle was achieved through an increase in mean cell length (24%) and the addition of new sarcomere units in series. Exercise induced no acceleration of capillary growth in either ventricle, leading to significant decreases in the capillary luminal volume density (-21%) and surface density (-16%) in the right ventricle. Such alterations in the structural properties of the microvasculature implicated in oxygen availability and diffusion suggest that vigorous exercise, even after a preconditioning period, may still be detrimental to the myocardium. The techniques of myocardial morphometry were examined with respect to potential errors associated with oblique tissue sections and the use of light versus electron microscopy for cell counting. It was shown that the practical effects of obliquity are negligible and that electron microscopic resolution is essential.