Venous Stent Migrating to the Right Heart Causing Severe Regurgitation

Venous stent migration to the cardiopulmonary system is a rare but serious complication. Cardiopulmonary involvement has various presentations such as valvulopathy, acute heart failure, arrhythmias, endocarditis, and tamponade. The presenting symptoms depend on the eventual location of the stent in the heart or lungs, size of the stent, and valve involvement. Extracardiac dislodgement can be managed by catheter-directed extraction or proper deployment within the containing vessel or surgical extraction. Intracardiac stents may require open surgery to prevent life-threatening complications. We present an asymptomatic patient with stent migration that lead to severe tricuspid regurgitation and required tricuspid valve replacement

Aneurysm Formation After Laser-Assisted Microvascular Anastomosis: Etiology, Growth Rate, and Prevention

Aneurysm formation has been a major complication in laser-assisted micro vascular anastomosis (LAMA). The authors investigated the effect of increased laser energy on the formation and growth rate of aneurysms. In addition, possi ble methods of prevention were reviewed. End-to-end anastomoses were per formed on 89 rat femoral arteries with the placement of three stay sutures (120 degrees apart) followed by application of CO2 laser irradiation (power = 80 mW, pulse mode = 0.2 s, spot size = 0.275 m). In Group I (N=55), anasto moses were performed with 45 laser pulses, and in Group II (N = 34) 135 laser pulses were used. Each disruption of an anastomosis was repaired by use of 15 additional laser pulses. Six of 18 aneurysms in Group I were reevaluated at weeks 1, 3, and 8 to assess growth rate. All vessels were examined at week 3 for patency and aneurysm formation.

Overall aneurysm rates in the two groups were similar, despite the increased laser energy used in Group II (p > 0.05). There was a higher incidence of aneu rysm formation in disrupted vessels in both groups when compared with non- disrupted vessels (p < 0.05 in Groups I and II). The aneurysm rates did not differ between the two groups when vessels with no disruption or with 1 disrup tion were compared (p > 0.05). Mean aneurysm size increased 0.4 mm/week during the first week, 0.25 mm/week during the second and third weeks, and less than 0.1 mm/week during the remaining five weeks.

In conclusion, the authors have shown that aneurysm formation is not re lated to the total amount of laser energy applied and that disrupted anastomoses have higher aneurysm rates independent of laser energy. Aneurysm growth rate is maximal during the first week.

Hemodynamic effects of carbon dioxide insufflation during endoscopic vein harvesting

BACKGROUND

A prospective study was performed assessing the hemodynamic effects of carbon dioxide (CO2) insufflation during endoscopic vein harvesting (EVH) using the Guidant Vasoview Uniport system.

METHODS

Five hemodynamic and respiratory parameters (end-tidal carbon dioxide, arterial partial pressure of carbon dioxide, mean arterial pressure, mean pulmonary arterial pressure, and cardiac output), were measured in 100 consecutive patients undergoing EVH with CO2 insufflation. Data were obtained prior to commencement of EVH, 15 minutes after commencement, and 5 minutes after completion of the vein harvesting.

RESULTS

No adverse hemodynamic effects were observed during CO2 insufflation. Specifically, average mean arterial pressure went from 88.77+/-9.64 to 89.13+/-8.60 to 88.24+/-8.71 mm Hg before, during, and after endoscopic vein harvesting (p = 0.291). Likewise, average mean pulmonary artery pressures were 19.76+/-4.75, 20.05+/-4.48, and 20.05+/-4.62 mm Hg (p = 0.547); and average cardiac output was 4.25+/-0.74, 4.22+/-0.73, and 4.23+/-0.69 L/min (p = 0.109) at those three intervals. Additionally, there was no evidence of significant systemic absorption of CO2 as reflected in average arterial PCO2, which remained steady at 37.42+/-5.19, 37.51+/-4.59, and 38.10+/-4.80 mm Hg (p = 0.217); and average end-tidal CO2, which was 32.10+/-3.66, 32.50+/-3.47, and 32.38+/-3.33 mm Hg (p = 0.335). In a subset of 20 patients with elevated pulmonary arterial pressure (more than 32 mm Hg), there was also no significant change in any of the parameters.

CONCLUSIONS

Carbon dioxide insufflation during EVH leads to no adverse hemodynamic consequences or systemic CO2 absorption. The technique appears to be safe and well tolerated.

Activation of creatine kinase-B and phospholamban gene expression in transformed latissimus dorsi muscle: evaluation of mRNA by polymerase chain reaction

Latissimus dorsi muscle (LDM) transformation following chronic stimulation is the critical requirement for its use in cardiac assist procedures. In order to identify one or two molecular markers that can be used to effectively monitor the LDM transformation, the modulation in the expression of creatine kinase (CK) and phospholamban (PLB) genes by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was examined. Continuous in situ stimulation of left LDM was performed in four dogs for a period of 10 weeks after a vascular delay period of 2 weeks following surgery. For RT-PCR, gene-specific radiolabeled primers and equal amounts of cDNA synthesized from total RNA extracted from the LDM biopsies obtained at 4, 7, and 10 weeks of stimulation were used. A 2.6-fold increase in creatine kinase (brain type) (CK-B) mRNA was observed at transformed LDM compared to the control (P = 0.004) following 10 weeks of stimulation. On the contrary, a 30% decline was observed in creatine kinase (muscle type) (CK-M) mRNA level. An increase up to eight-fold was also observed in PLB mRNA in stimulated LDM compared to the contralateral muscle (P = 0.002). The PLB mRNA level in transformed LDM reached plateau and became comparable to that of normal heart after 7 weeks of stimulation. However, a sustained increase in CK-B mRNA level was observed until 10 weeks of stimulation. The level of beta-actin mRNA used as control remained the same in both stimulated and control samples. Thus the increase in CK-B and PLB mRNA and downregulation of CK-M mRNA in transformed LDM, demonstrated here by RT-PCR, indicate a switch from anaerobic to aerobic potential of transformed LDM along with a change towards slow-twitch phenotype and provide valuable markers to monitor the effectiveness of muscle transformation in cardiomyoplasty.

Comparative study of biological glues: cryoprecipitate glue, two-component fibrin sealant, and "French" glue

BACKGROUND

Although biological glues have been used clinically in cardiovascular operations, there are no comprehensive comparative studies to help clinicians select one glue over another. In this study we determined the efficacy in controlling suture line and surface bleeding and the biophysical properties of cryoprecipitate glue, two-component fibrin sealant, and "French" glue containing gelatin-resorcinol-formaldehyde-glutaraldehyde (GRFG).

METHODS

Twenty-four dogs underwent a standardized atriotomy and aortotomy; the incisions were closed with interrupted 3-0 polypropylene sutures placed 3 mm apart. All dogs had a 3- by 3-cm area of the anterior wall of the right ventricle abraded until bleeding occurred. The animals were randomly allocated into four groups: in group 1 (n = 6) bleeding from the suture lines and from the epicardium was treated with cryoprecipitate glue; in group 2 (n = 6) bleeding was treated with two-component fibrin sealant; group 3 (n = 6) was treated with GRFG glue; group 4 (n = 6) was the untreated control group. The glues were also evaluated with regard to histomorphology, tensile strength, and virology.

RESULTS

The cryoprecipitate glue and the two-component fibrin sealant glue were equally effective in controlling bleeding from the aortic and atrial suture lines. Although the GRFG glue slowed bleeding significantly at both sites compared to baseline, it did not provide total control. The control group required additional sutures to control bleeding. The cryoprecipitate glue and the two-component fibrin sealant provided a satisfactory clot in 3 to 4 seconds on the epicardium, whereas the GRFG glue generated a poor clot. There were minimal adhesions in the subpericardial space in the cryoprecipitate and the two-component fibrin sealant groups, whereas moderate-to-dense adhesions were present in the GRFG glue group at 6 weeks. The two-component fibrin sealant was completely reabsorbed by 10 days, but cryoprecipitate and GRFG glues were still present. On histologic examination, both fibrin glues exhibited minimal tissue reaction; in contrast, extensive fibroblastic proliferation was caused by the GRFG glue. The two-component and GRFG glues had outstanding adhesive property; in contrast, the cryoprecipitate glue did not show any adhesive power. The GRFG glue had a significantly greater tensile strength than the two-component fibrin sealant. Random samples from both cryoprecipitate and the two-component fibrin glue were free of hepatitis and retrovirus.

CONCLUSIONS

The GRFG glue should be used as a tissue reinforcer; the two-component fibrin sealer is preferable when hemostatic action must be accompanied with mechanical barrier; and finally, the cryoprecipitate glue can be used when hemostatic action is the only requirement.

Effect of cerebrospinal fluid drainage and/or partial exsanguination on tolerance to prolonged aortic cross-clamping

Paraplegia as a consequence of spinal cord ischemia associated with procedures on the thoracic and thoracoabdominal aorta has been linked to the interaction of proximal hypertension with elevated cerebrospinal fluid pressure (CSFP) during aortic cross-clamping (AXC). CSFP reduction via cerebrospinal fluid (CSF) drainage is thought to significantly prolong the cord's tolerance to AXC. Likewise, partial exsanguination is reported to effectively reduce ischemic injury by controlling proximal hypertension. To evaluate the individual and collective efficacy of both techniques, 18 mongrel dogs (25 to 35 kg), divided into three equal groups, underwent a fourth interspace left thoracotomy AXC. Baseline proximal arterial blood pressure (PABP), distal arterial blood pressure (DABP), and CSFP were established and monitored at 5-minute intervals during 120 minutes of AXC, and for 30 minutes thereafter. Group I animals were partially exsanguinated prior to AXC to maintain PABP at a mean of 115 to 120 mmHg. Group II animals had sufficient (16 +/- 5 cc) CSF withdrawn to maintain a DABP-CSFP gradient, i.e., spinal cord perfusion pressure (SCPP) of 20 mmHg. Group III animals were treated with both CSF drainage and partial exsanguination in the same manner as groups I and II, respectively. Perioperative somatosensory evoked potential (SEP) monitoring evaluated cord function. Postoperative neurological outcome was assessed with Tarlov's criteria. SEPs degenerated approximately 22 minutes following AXC for groups II and III. In contrast, group I exhibited rapid (10 +/- 7 min) SEP loss. All five surviving group I animals displayed paralysis 48 hours postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipomatous hypertrophy of the interatrial septum

Lipomatous hypertrophy of the interatrial septum, a finding associated with obesity and advancing age, consists of accumulation of adipose tissue including fetal adipose tissue in the interatrial septum. It is a rare lesion of the heart and can reach notable size. A case is reported in which the diagnosis of lipomatous hypertrophy of the interatrial septum was established intraoperatively; the large bulk of the lipoma was such that it required major reconstruction of the interatrial septum and right and left atrial walls.

Dynamic cardiomyoplasty: left ventricular diastolic compliance at different skeletal muscle tensions

The possible limitation of left ventricular (LV) relaxation during diastole is a concern for clinicians and researchers utilizing dynamic cardiomyoplasty. This study was designed to evaluate the LV compliance at three different skeletal muscle tensions, in a normal heart and in a failing heart, created by propranolol infusion (11.6 mg/kg). A biventricular latissimus dorsi muscle (LDM) wrap was performed in 10 dogs. The LV pressure (Millar) and two minor axis dimensions (endocardial crystals) were measured. LV pressure-volume loops were constructed, and LV diastolic compliance was calculated. The measurements were obtained before wrap and after wrap at different LDM tensions with 0, 5, and 10 volts stimulation each time. These measurements were repeated after propranolol treatment. The results showed that LV diastolic compliance (dV/dP) was 1.79 before wrap and about 0.7 after wrap, and after propranolol, at various tensions and stimulations. LDM wrap decreased LV compliance significantly. LV compliance was not significantly affected by changing tension or voltage of stimulation in either the failing or the non-failing heart. The reduction in compliance may be an indication that LDM wrap causes a limitation of LV relaxation, which is one of wrap's deleterious effects.

Acute mesenteric ischemia after cardiopulmonary bypass

Three thousand sixty-six patients underwent cardiopulmonary bypass at the Maimonides Medical Center over a 5-year period from January 1, 1987, to January 1, 1992. Of these patients, 1,890 (62%) were less than 70 years of age, 969 (32%) ranged from 70 to 79 years of age, and 207 (7%) were 80 years of age or older. The overall 30-day mortality rate was 8%. Eleven patients developed acute mesenteric ischemia from 24 hours to 12 days postoperatively. At the time of diagnosis, the majority of patients presented with late classical signs and symptoms of acute mesenteric ischemia including abdominal distension, respiratory distress, hypotension, oliguria, and sepsis. All patients underwent immediate laparotomy. Extensive bowel necrosis was found in all, and resection was possible in eight patients. All patients died as a result of this complication. Using the exact trend test, we found a statistically significant increase in the incidence of deaths due to acute mesenteric ischemia after cardiopulmonary bypass in older compared with younger patients. This fatal complication after cardiopulmonary bypass occurs more often than previously believed and is a relatively common cause of death in the elderly.

The relationship between timing of repair of disruptions and subsequent aneurysm formation in laser-assisted microvascular anastomoses

In this study we investigated the effects of duration of bleeding after laser-assisted microvascular anastomoses and the amount of laser energy used to control bleeding on aneurysm formation. Eighty femoral arteries were exposed in 40 Sprague-Dawley rats anesthetized with chloral hydrate. The arteries were transected and then anastomosed end-to-end with three nylon stay sutures followed by irradiation of the vessels with energy from a CO2 laser. The laser power was kept at 90 mW, and each of three segments between stay sutures was exposed for 6 seconds to continuous laser energy. If anastomotic disruption (defined as bleeding after completion of the anastomosis) occurred, it was controlled with pressure over the disrupted site for 10, 25, or 40 seconds. Disruptions were required with exposure to additional laser energy for either 6 (group 1) or 12 seconds (group 2). The anastomoses were inspected at 21 days postoperatively to assess patency and aneurysm formation. Twenty-six of 80 vessels (32%) were anastomosed without the occurrence of disruptions: these 26 vessels had a 100 per cent patency rate and did not develop aneurysms. In group 1, the incidence of redisruption following a primary disruption was the same irrespective of duration of bleeding (4/8, 3/6, and 3/6 for 10-, 25-, and 40-seconds bleeding time, respectively P = NS). Similarly, there was no difference in the incidence of aneurysm formation in this group (0/8, 2/6, and 2/6 for 10, 25, and 40", respectively, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Intrathecal perfusion of an oxygenated perfluorocarbon prevents paraplegia after aortic occlusion

A canine model was used to evaluate the effects of continuous intrathecal perfusion of an oxygenated perfluorocarbon emulsion on systemic and cerebral hemodynamics and neurologic outcome after 70 minutes of normothermic aortic occlusion. Twelve mongrel dogs were instrumented to monitor proximal and distal arterial blood pressure, cerebrospinal fluid pressure, spinal cord perfusion pressure, and somatosensory evoked potentials. The intrathecal perfusion apparatus consisted of two perfusing catheters, placed in the intrathecal space through a laminectomy, and a draining catheter percutaneously inserted in the cisterna cerebellomedullaris. The aorta was cross-clamped just distal to the left subclavian artery for 70 minutes. Animals were randomized into two groups: group 1 (n = 6) animals were treated with intrathecal perfusion of saline solution, whereas group 2 (n = 6) animals received oxygenated Fluosol-DA 20%. Data were acquired at baseline, during the cross-clamp period, and after reperfusion. Normothermic Fluosol or saline solution was infused at a rate of 15 mL/min beginning 15 minutes before cross-clamping and continued throughout the ischemic interval. There was no difference in proximal arterial blood pressure (97.2 versus 95.4 mm Hg; p > 0.05) or distal arterial blood pressure (14.6 versus 15.0; p > 0.05) between the two groups throughout the cross-clamp interval. Cerebrospinal fluid pressure rose significantly in both groups with the onset of intrathecal perfusion of either saline solution or Fluosol (7 +/- 1 versus 24 +/- 5 and 8 +/- 1 versus 40 +/- 4 mm Hg, respectively; p < 0.05). The rise in cerebrospinal fluid pressure was sustained throughout the perfusion interval in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Internal mammary artery bypass: thirteen years of experience. Influence of angina and survival in 5125 patients

Internal mammary artery (IMA) bypass to the anterior descending coronary artery (ADA) was performed in 5125 patients from January 1978 to December 1990. The average age of patients was 68 years; males accounted for 68% (3485 patients) and 82% (4203) were NYHA Class III. Left ventricular function was impaired (ejection fraction < 40%) in 68% (3485 patients). The average number of additional saphenous vein graft (SVG) per patient was 2.2. Operative mortality was 1.8%. Mediastinitis occurred in 51 patients (1.0%). Reoperation for bleeding was necessary in 56 patients (1.1%). Perioperative myocardial infarction was seen in 102 patients (2.0%) and neurological complications occurred in 51 patients (1%). Repeat coronary angiography was performed in 1414 patients (28%) and demonstrated a patency rate of 96% in IMA grafts and 75% in SVG grafts (p < 0.001). Survival at 13 years was 80% from all causes and 90% when non-cardiac deaths were excluded. Recurrence of angina occurred in 768 patients (15%) and reoperation or PTCA was performed in 61 (1.2%). During the same time period, 2345 patients underwent coronary artery bypass utilizing solely SVG. Survival at 13 years was 68% from all causes and 78% when non-cardiac deaths were excluded (p < 0.001). Recurrent angina was present in 727 patients (31%) (< 0.001). This data suggests that long-term probability of cumulative survival and occlusion free survival were significantly greater and the probability of recurrent angina and reoperative CABG and death from cardiac causes were significantly less in the IMA patients and should be the conduit of choice in coronary bypass surgery.

Aortoventriculoplasty in the management of an infected Cabrol graft

This report describes use of a modified aortoventriculoplasty (Konno procedure) for reoperation on a patient with prosthetic aortic valve conduit endocarditis. The modified Konno procedure was necessary to expose the mid-left ventricular outflow tract to reconstruct an aortic annulus.

A multimodality approach lengthens warm ischemic time during aortic cross-clamping

To evaluate the effects of exsanguination, cerebrospinal fluid drainage (CSFD), steroids alone and in conjunction with CSFD on spinal cord perfusion pressure (SCPP), and neurological outcome following 70 min of normothermic spinal cord ischemia, we monitored proximal (Px BP) and distal (Ds BP) aortic blood pressure, cerebrospinal fluid pressure, and somatosensory evoked potentials (SEP) in 29 mongrel dogs. In all animals Px BP during aortic cross-clamping was controlled with partial exsanguination (40-50% circulating blood volume). Dogs were randomized into four groups (gp): gp 1 (n = 6) control; gp 2 (n = 8) steroids only (methylprednisolone 30 mg/Kg 10 min before aortic occlusion and 4 hr later); gp 3 (n = 8) CSFD only; gp 4 (n = 7) steroids and CSFD. Partial exsanguination effectively controlled Px BP during aortic cross-clamping in all groups. After the statistically significant decrease from preclamp values, mean Px BP did not differ among groups (78.9, 81.2, 80.5, and 80.3 mm Hg, respectively, P greater than 0.05). Mean Ds BP decreased from systemic values to 12.6, 16.8, 16.7, and 17 mm Hg, respectively, after aortic occlusion (P less than 0.05); these values did not differ from one another. CSFP did not change significantly from its baseline value while the aorta was cross-clamped in gp 1; CSFP was significantly reduced to 6.2 mm Hg in gp 2, steroid-treated animals (P less than 0.05 vs gp 1); a further significant reduction in CSFP was noted in gp 3 and 4 undergoing CSFD (0.07 and 0.67 mm Hg, respectively, P less than 0.05 vs gp 1 and 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Internal mammary coronary artery anastomosis by CO2 laser: an acute experimental study

This study was designed to determine the feasibility of anastomosing the internal mammary artery (IMA) and coronary artery with a carbon dioxide laser in a canine model. Twenty-two mongrel dogs were randomly assigned to two groups: group I (n = 11) underwent laser-assisted vascular anastomosis (LAVA) of the left IMA to the left anterior descending (LAD) coronary artery, whereas in group II (n = 11) the anastomosis was done with the conventional technique (handsewn). Laser methodology was used to micro-weld vessels utilizing a power of 200 mW with a spot size of 500 mu, producing an effective power density of 102 W/cm2 and energy fluence of 9,172 joules/cm2 in a continuous mode at a distance of 2 cm. The short-term patency rate, measured at 2 hours after completion of the anastomosis, was 100% in both groups. The time required to perform the LAVA in group I was significantly shorter than group II (6.27 +/- 0.47 vs 11.6 +/- 0.67 min, p less than 0.05). The mean anastomotic bursting pressure in group I was significantly lower compared to group II (348 +/- 8 vs 402 +/- 9 mmHg, p less than 0.05). Histologic evaluation of all vessels showed moderate thermal injury of the adventitia and media in the laser group. Scanning electron microscopy exhibited a smooth anastomotic area in group I, whereas endothelial and perianastomotic changes with multiple needle craters occurred in group II (conventional anastomosis).(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of right atrial infusion of PGE1 in sepsis-induced pulmonary hypertension

In this study we investigated the effects of right atrial infusion of PGE1 (RAIPGE1) in doses from 40 to 500 ng/kg/min on sepsis-induced pulmonary artery hypertension (SIPAH). Thirteen pigs were randomized into a time-course group (n = 6) and a PGE1-treated group (n = 7). Pulmonary hypertension (PAH) was induced with the infusion of Pseudomonas Aeruginosa (PsAr) at a concentration of 2 X 10(8) CFU/20 kg/min in both groups. The infusion of PsAr caused a significant and persistent rise in mean pulmonary artery pressure (MPA), pulmonary vascular resistance (PVRI), right ventricular compliance (RVC), RV dp/dt, and right ventricular stroke work index (RVSWI), 30 min after the onset of infusion (P less than 0.05 vs baseline). Systemic hemodynamics and gas exchange were not affected throughout the 3-hr period of infusion (P = NS); however, left ventricular compliance (LVC) was depressed at a MPA greater than 35 mm Hg. The RAIPGE1 following SIPAH caused a concentration-dependent reduction above 40 ng/kg/min of MPA, PVRI, RVSWI, and RV dp/dt (P less than 0.05, 120 and 500 ng/kg/min vs PAH). RVC returned to baseline values during the infusion of PGE1. Systemic hemodynamics, including oxygen delivery and extraction, were unaffected by the infusion of PGE1, but LVC was improved (P less than 0.05, PGE1 500 vs PAH). The infusion of PGE1 caused a concentration-dependent rise in shunt fraction (Qs/Qt) and alveolararterial oxygen gradients which reached statistical significance during the infusion of 500 ng/kg/min. Our data show that RAIPGE1 is effective in ameliorating RV and pulmonary hemodynamics, but at the largest dose it negatively affects gas exchange.

Influences of laser pulse duration and anastomotic disruption on laser-assisted microvascular anastomoses (LAMA)

The success rate of laser-assisted microvascular anastomosis (LAMA) can be influenced by many factors, including the parameters of the laser technique used. This study examined the effects of laser pulse duration and the occurrence of anastomotic disruption immediately following first repair attempts on the incidence of aneurysm formation and the patency rate in LAMA. Fifty transected rat femoral arteries in 25 rats were anastomosed with three stay sutures and welded with a CO2 laser at a power of 80 mW. In each rat, the laser was applied in the form of 45 pulses of 0.2 sec duration to one femoral artery (group 1) and in the form of 15 pulses of 0.6 sec duration to the contralateral femoral artery (group 2). Comparison of group 1 with group 2 showed that overall rates of aneurysm formation (30% vs. 17%) and patency rates (92% vs. 96%) did not differ significantly (P less than 0.05) at 3 weeks postoperatively. However, disrupted vessels in both groups had a significantly higher incidence of subsequent aneurysm formation than nondisrupted vessels (54% vs. 0% in group 1, P less than 0.05; 43% vs. 6% in group 2, P less than 0.06; groups 1 and 2 pooled, P less than 0.001). These findings indicate that changes in laser pulse duration such as those tested do not affect the aneurysm and patency rates of LAMA. The results demonstrate, however, that disruption after laser welding plays a significant role in subsequent aneurysm formation.

Demographic changes in coronary artery bypass surgery and its effect on mortality and morbidity

Over the past 4-5 years, possibly with the advent of percutaneous transluminal coronary angioplasty (PTCA), there has been a changing patient population for coronary artery bypass surgery (CABS) with a gradual increase in the operative mortality. In an attempt to analyze the changing demographics in patients undergoing CABS and its effect on operative mortality, we analyzed data from 5536 consecutive patients undergoing isolated CABS. There was 4151 patients less than 70 years of age and 1385 patients greater than 70 years. Reoperative CABS procedures were performed in 385 patients, and CABS for post infarction unstable angina pectoris was performed in 578 patients. During the same time period, 2910 patients underwent PTCA. The mean age of bypass patients was 68.5 years with 38% being 70 years or older. The left ventricular ejection fraction in patients undergoing CABS averaged 38%. The average number of bypasses performed was 3.1. In comparison, patients presenting for PTCA were younger (average age 55), had normal ejection fractions (average 55%) and were predominantly treated for single or double vessel disease. The hospital mortality for elective CABS in patients less than 70 years of age was 1.8%, for reoperative CABS 3.6%, for post infarction unstable angina pectoris 4%, and for patients greater than 70 years 8%, for a combined operative mortality of 4.8%. These data suggest that because of the increasing number of elderly patients (greater than 70 years of age), and the increasing number of reoperative CABS cases and acute myocardial infarction patients with unstable angina pectoris presenting for CABS, the operative mortality will continue to rise.

Effect of sternotomy and coronary bypass surgery on postoperative pulmonary mechanics. Comparison of internal mammary and saphenous vein bypass grafts

Coronary artery bypass grafting (CABG) is commonly performed via a median sternotomy with a reversed saphenous vein (SV) and/or an internal mammary artery (IMA) graft. Sternotomy and IMA harvesting may adversely affect postoperative respiratory function (PFTs) as disruption of the sternun may impair chest wall stability, and the decrease in intercostal muscle blood supply after removal of the IMA may reduce the force of respiration. We compared preoperative and six- to eight-week postoperative PFTs in patients undergoing CABG. The results were independent of age, sex, number of grafts, aortic cross clamp time, duration of bypass run, and postbypass fluid gradient. It was concluded that sternotomy caused a decrease in postoperative PFTs and that IMA harvesting may be accompanied by greater impairment in PFTs than when SV grafts alone were used.

Internal mammary artery bypass grafting: influence on recurrent angina and survival in 2,100 patients

Internal mammary artery (IMA) bypass grafting to the anterior descending coronary artery was performed in 2,100 patients between January 1978 and July 1986. The average number of additional saphenous vein grafts (SVGs) per patient was 1.8. During the same period, 1,753 patients underwent coronary artery bypass grafting using an SVG (average number of grafts per patient, 3.2). The average patient age was similar: 62.3 years for IMA grafts and 64.7 years for SVGs. Men constituted two thirds of each group. Left ventricular function was impaired (ejection fraction less than 45%) in 1,071 (51%) of IMA grafts and 847 (48.3%) of SVGs. Other aggregate risk factors, ie, elevated blood pressure, diabetes mellitus, previous myocardial infarction, and congestive heart failure, were similar in each group. Operative results and postoperative mortality of the IMA and SVG patients were comparable. However, the long-term probability of cumulative survival and occlusion-free survival were significantly greater and the probability of recurrent angina and reoperative coronary artery bypass grafting were significantly less in IMA graft patients (p less than 0.015). The relative risk of occlusion in an SVG was 4 to 5 times greater than that of the IMA graft. These data indicate that a patent IMA graft to the anterior descending coronary artery protects against recurrent angina and death from cardiac-related causes, and that the IMA should be the conduit of choice.

Internal mammary artery bypass: effect on longevity and recurrent angina pectoris in 2900 patients

Internal mammary artery bypass (IMA) to the anterior descending coronary artery was performed in 2900 patients from January 1978 to December 1987. The average age of the patients was 64 years. Males accounted for 68% (1972 patients) and 82% (2378 patients) were in New York Heart Association (NYHA) class III. Left ventricular function was impaired in 51%. The average number of additional saphenous vein grafts per patient was 1.8. The operative mortality was 1.6%. Mediastinitis occurred in 29 patients (1%). Reoperation for bleeding was necessary in 32 patients (1.1%). Perioperative myocardial infarction (MI) was seen in 58 patients (2%) and neurological complications occurred in 32 patients (1.1%). Repeat coronary angiography was performed in 703 patients (25%) and demonstrated a patency rate of 96% in IMA grafts and 81% in saphenous vein grafts (SVG). Survival at 9 years was 90% from all causes and 95% when noncardiac deaths were excluded. Recurrence of angina occurred in 522 patients (18%) and reoperation was performed in 15 patients (0.5%). During the same time period, 1783 patients underwent coronary artery bypass utilizing a SVG. Survival at 9 years was 78% from all causes and 83% when noncardiac deaths were excluded. Recurrent angina was present in 546 patients (39%). These data suggest that a patent-IMA to the anterior descending protects against recurrent angina and death from cardiac causes and should be the conduit of choice.

Coronary artery bypass in septuagenarians. Analysis of mortality and morbidity

Elective coronary artery bypass surgery can be performed with an expected operative mortality of 1-3%. However, the effects of age on morbidity and mortality in patients undergoing this procedure remain controversial. To analyze morbidity and mortality in septuagenarians undergoing isolated coronary artery bypass surgery, we compared the results in 685 septuagenarians with those in 3,142 patients under the age of 70 years, all of whom underwent this procedure from January 1981 to December 1986. A larger percentage of elderly patients had triple-vessel disease (89% vs. 71%), left main coronary artery obstruction (34% vs. 16%), and ejection fractions less than 45% (68% vs. 41%). A larger percentage of septuagenarians had perioperative myocardial infarction (8% vs. 2%), required prolonged ventilatory support (10% vs. 3%), and had major neurological complications (4% vs. 1%). Mortality rates were significantly higher in elderly patients (7% vs. 2%) but did not correlate with the severity of coronary artery disease, the anginal pattern, or the diminishment of ventricular function. Major causes of mortality were pulmonary failure, renal failure, or both, sepsis, and neurological complications. These data suggest that elderly patients have an increased risk of cardiac and noncardiac morbidity and mortality after coronary artery bypass surgery. Higher mortality rates in this age group appear attributable to noncardiac organ failure. Late follow-up studies failed to show any significant difference among patients based on age alone.

Repair of ventricular rupture following mitral valve replacement

Left ventricular rupture is reported to occur in 0.5-2% of patients following mitral valve replacement and results in a high mortality rate. Three types of left ventricular rupture have been identified, each attributed to a different mechanism. Failure of repair has been due to repeated tearing of the ventricular muscle and resulting hemorrhage. We describe the repair of left ventricular rupture following mitral valve replacement with buttressed dacron patch. The repair is designed to eliminate the tension placed on the suture line. In addition, specific recommendations are made to avoid left ventricular rupture during mitral valve replacement.

Effect of blood bonding on bursting strength of laser-assisted microvascular anastomoses

This experiment evaluated the influence of blood on the weld strength of laser-assisted microvascular anastomoses (LAMA). Rat femoral arteries were anastomosed end-to-end by either direct laser welding (group I) or by a blood-bonded technique (group II) whereby fresh blood was applied to the vessel edges before laser exposure. Bursting strength was measured at 0, 1, and 24 hours and at 3 and 7 days by infusing methylene blue into the vessel while pressure was monitored. The results showed significantly increased bursting strength in group II compared with group I at 0 hour and 7 days (P less than 0.05). There was a significant increase in bursting strength in group I from 0 hour to 1 hour (P less than 0.05). It is concluded that blood-bonding enhances the early bursting strength of LAMAs and may facilitate arterial wall healing.

Results of open heart surgery in patients with recent cardiogenic embolic stroke and central nervous system dysfunction

Patients undergoing open heart surgery who have had recent cardiogenic embolic stroke or have central nervous system dysfunction pose a difficult management problem. There is always the risk that cardiopulmonary bypass and heparinization may exacerbate the neurologic injury. There is no clear data indicating what is a safe interval of time from the onset of neurologic symptoms to the time of surgery. Since 1982 we have operated on 15 patients with recent (2 to 28 days, mean 12.7 +/- 7.9 days) neurologic injury. Indications for surgery included recurrent embolization, sepsis, and hemodynamic deterioration. Three patients were comatose with no focal neurologic signs at the time of surgery, and 12 patients had focal neurologic deficits. All patients had preoperative computed tomographic scans. Embolic cerebral infarctions were documented in 12 patients, one patient had evidence of intracranial hemorrhage, and one patient had a subdural hematoma. Fourteen patients had native or prosthetic valvular endocarditis and one patient had a left atrial myxoma. All patients underwent corrective cardiac surgery. One patient died in the postoperative period from multisystem failure; all other patients have been followed since discharge (6 months to 4 years). All surviving patients demonstrated improvement in their neurologic symptoms and eight patients had complete neurologic recovery. The results of this study indicate that open heart surgery can be safely performed in patients with recent neurologic injury.

Role of coronary angiography and coronary artery bypass surgery prior to abdominal aortic aneurysmectomy

It is well recognized that patients with abdominal aortic aneurysms have a high incidence of coronary artery disease, and that the major cause of death in patients undergoing aneurysmectomy has been acute myocardial infarction. In order to assess the incidence of significant coronary artery disease, cardiac catheterization was performed on 42 consecutive patients with abdominal aortic aneurysms. Thirty-six patients (85.7%) had significant anatomic coronary artery disease. Interestingly, all 8 patients with ejection fractions of less than 50% had triple vessel disease or left main disease, and 12 of 34 patients with ejection fractions greater than or equal to 50% had triple vessel disease or left main disease. Of the 30 patients who were NYHA Class I or Class II, 14 (46.7%) had triple vessel disease or left main disease. All 20 patients with triple vessel disease or left main disease underwent myocardial revascularization 7 to 10 days prior to abdominal aneurysmectomy. No patients had a perioperative myocardial infarction either following coronary artery bypass surgery or abdominal aortic aneurysm resection, and there were no operative mortalities. Although this was not a randomized study, it would seem from these results that in selected patients, myocardial revascularization prior to abdominal aneurysmectomy can decrease the incidence of acute myocardial infarction and also decrease operative mortality. It is presently recommended that all symptomatic patients, patients with ejection fractions of less than 50%, and asymptomatic patients with ejection fractions of greater than or equal to 50% with positive exercise radionuclide angiography undergo cardiac catheterization prior to aneurysmectomy, and those patients with left main disease or severe coronary artery disease undergo myocardial revascularization prior to aneurysm resection.

Use of profound hypothermia and circulatory arrest in complex intra-cardiac repair in adults

Profound hypothermia and circulatory arrest is a well worked out technique for total repair of congenital defects in infants. Recently, it has been popularized for the repair of aneurysms of the transverse aortic arch. We have applied this technique of profound hypothermia and circulatory arrest in three other adult patients in whom conventional techniques would not allow safe and adequate complete repair of acquired intra-cardiac defects. The first patient, a 76-year-old female, had a large chronic ascending aortic aneurysm involving the aortic valve, as well as the innominate and left common carotid arteries. Resuspension of the aortic valve, resection of the ascending aneurysm, and reconstruction of the ascending and transverse aorta were performed under profound circulatory arrest. In addition, multi-dose hypothermic blood K+ cardioplegia was utilized to protect the myocardium. The second patient underwent valve replacement during a period of circulatory arrest because of extensive calcification of the entire ascending aorta and transverse aortic arch. Arrest time was 56 minutes. The third patient was a 54-year-old female and had a large patent ductus arteriosus with a 3:1 left-to-right shunt as well as significant aortic and mitral valve disease. The ductus was closed through an incision in the pulmonary artery during a 13-minute period of profound hypothermia and circulatory arrest. Aortic valve replacement and mitral repair were also performed at the same time, utilizing conventional techniques. All three patients recovered uneventfully with no evidence of any significant neurologic defect. Long-term follow-up has shown improvement in functional classification in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of right ventricular unloading during right coronary artery occlusion in an experimental model

This investigation examined the efficacy of right atrial-pulmonary artery bypass (RA-PA) during acute ischemia of the right ventricle. The right coronary artery (RCA) was ligated in 25 open chest, open pericardium sheep. Control animals (n = 15) were resuscitated with only intravenous fluids. In the experimental animals (n = 10) RA-PA bypass was initiated 5 minutes after right coronary occlusion. Sixty percent (9/15) of the control animals died within 90 minutes of RCA occlusion from refractory ventricular arrhythmia or right ventricular failure. Four of 10 RA-PA animals died within 2 hours of RCA occlusion from severe pulmonary hemorrhage and arterial oxygen desaturation when high flow rates (2.5 to 3.5 L/min) were initially instituted. In these animals, lung histologic findings demonstrated extensive hemorrhage into the alveolar spaces. After 6 hours of RCA occlusion in the six surviving control animals, there were significant increases in central venous pressure and right ventricular end-diastolic cord length (relative ventricular volume change measured by ultrasonic crystal analysis), and a significant decrease in the cardiac output. In contrast, during RCA occlusion in the six surviving animals on RA-PA bypass, cardiac output was well maintained, and there was a significant decrease in central venous pressure and end-diastolic length. The percent of change from baseline in end-diastolic length correlated inversely with the percent of change from baseline in cardiac output (r = -0.81, p less than 0.01). By crystal violet and triphenyltetrazolium chloride dye techniques, the mean percentage area of necrosis to area of risk was significantly less for the RA-PA group compared with the control group (5.6% versus 67.1%, p less than 0.0001). In this experimental model, RA-PA bypass effectively unloaded the acutely ischemic right ventricle, maintained systemic cardiac output, and significantly reduced right ventricular infarction size. Further investigations with this ventricular support modality are needed to determine its effects on pulmonary pathophysiology.

Cryopreserved homologous saphenous vein: early and late patency in coronary artery bypass surgical procedures

Autologous saphenous vein has proved to be a satisfactory conduit for use in coronary artery bypass grafting. Unfortunately, it is not always available, and substitute material must sometimes be used. When satisfactory autologous veins were not available and the internal mammary arteries were unsuitable, cryopreserved homologous saphenous veins were used in 28 patients. A total of 76 grafts were constructed. Cryopreserved homologous veins were used for 61 grafts, autologous saphenous veins for 11 grafts, and the internal mammary artery for 2 grafts. Coronary angiography was performed 8 to 12 days postoperatively in 16 patients. Of the 31 homografts studied, 8 were occluded (26%), 3 were stenotic (9%), and 20 were normal (65%). The one internal mammary artery and six autologous veins studied were all patent. Six patients underwent late catheterization 6 to 12 months postoperatively. Thirteen homografts were studied at late catheterization: 11 were occluded, 1 was severely stenotic, and 1 was mildly stenotic. At late catheterization, the one internal mammary artery studied was patent, and the one autologous saphenous vein was 95% occluded. Results of both early and late catheterization performed on 18 patients demonstrated that of the 35 homografts studied, 17 (49%) were occluded, 3 (9%) had greater than 70% stenosis, 1 (3%) had mild disease, and 14 (40%) were free of disease. One year follow-up data obtained on 26 patients revealed that 4 patients (15%) died of cardiac causes, 2 patients (8%) died of noncardiac causes, 11 patients (42%) have recurrent angina, and 9 (35%) are asymptomatic. It is concluded that use of cryopreserved homologous saphenous veins for coronary artery bypass grafting should be avoided if at all possible.

Surgical results for mitral regurgitation from coronary artery disease

Results of coronary artery bypass grafting with and without mitral valve replacement were analyzed retrospectively in 101 patients with preoperative ischemic mitral regurgitation to determine the effects of severity and surgical treatment of mitral regurgitation on survival. Between 1980 and 1984, a total of 1,475 patients (mean age 59, 77% male) underwent coronary bypass. These patients were divided into three groups: (1) patients without ischemic mitral regurgitation who underwent isolated coronary bypass (1,374; 93%), (2) patients with ischemic mitral regurgitation who underwent isolated coronary bypass without valve replacement (85; 6%), and (3) patients with ischemic mitral regurgitation who underwent combined mitral valve replacement and coronary bypass (16; 1%). Preoperatively, patients with ischemic mitral regurgitation compared to those without regurgitation were significantly older (+6 years, p less than 0.001), had more severe coronary artery disease (p less than 0.001), a higher incidence of congestive heart failure (24% versus 5%, p less than 0.001) and recent myocardial infarction (16% versus 8%, p less than 0.01), and a lower mean ejection fraction (45% versus 61%, p less than 0.001). Operative mortality was significantly increased in patients with ischemic mitral regurgitation who underwent coronary bypass alone (p less than 0.01) and in those who underwent coronary bypass and mitral valve replacement (p less than 0.01)--11% and 19%, respectively--than in the coronary bypass patients without ischemic mitral regurgitation (3.7%). The severity of mitral regurgitation (0 to 4+) proved to be the most significant predictor of operative mortality. The actuarial survival rate at 5 years for the coronary bypass patients without ischemic mitral regurgitation was 85% compared to 91% (p less than 0.05) for the coronary bypass patients without ischemic mitral regurgitation. These results indicate that patients with ischemic mitral regurgitation have a higher prevalence of cardiac risk factors and are at an increased risk of operative mortality. Although the severity of the ischemic mitral regurgitation was strongly predictive of early survival, it proved to have an unexpectedly modest effect on long-term survival after surgical treatment.

Surgical management of infected median sternotomy: closed irrigation vs. muscle flaps

Mediastinitis remains a serious complication of median sternotomy which requires prompt and aggressive surgical management. Debridement and closed irrigation has been the conventional mode of treatment. Failure to respond results in open drainage and delayed healing with its associated increased morbidity and mortality. Secondary closure with rectus muscle flaps has been a marked advance in the treatment of these patients. In an attempt to define guidelines for the treatment of mediastinitis complicating median sternotomy, a retrospective review of 2,400 cardiac surgical cases at St. Vincent's Hospital from 1977 through 1982 was performed. There were 25 cases (1%) of mediastinitis. Debridement and closed irrigation was successful in 16 patients (64%) with an average postoperative hospital stay of 19 days. Failure resulted in open drainage in 2 patients (8%) with an average hospital stay of 66 days and debridement and secondary closure by rectus muscle flaps in 7 patients (28%) with an average hospital stay of 28 days. There were no deaths in the entire series. Failure to respond to closed irrigation was not due to delay in diagnosis. The length of time between operation and the first sign of sternal dehiscence did not vary significantly. Sternal dissolution, the presence of anaerobic organisms, large volumes of purulent and necrotic material, however, were responsible for continued mediastinitis and further sternal dehiscence. Open irrigation and delayed closure with muscle flaps should be reserved for these patients and appears to decrease significantly morbidity and length of hospital stay. Surgical debridement and closed irrigation, however, remains the primary method of treatment of the less virulent forms of mediastinitis following median sternotomy.

Analysis of morbidity and mortality in patients 70 years of age and over undergoing isolated coronary artery bypass surgery

With increasing frequency more elderly patients are referred for coronary artery bypass surgery. The operative results of 201 patients 70 years of age and over were compared with the results of 1242 patients under 70 years operated on since 1981. A larger percentage of the elderly patients had triple-vessel disease (66.2% vs 51.0%, p less than 0.001), left main coronary artery obstruction (34.8% vs 16.3%, p less than 0.01), and an ejection fraction of less than or equal to 45% (30.8% vs 21.1%, p less than 0.001). An increase percentage of the patients 70 years of age and over had perioperative myocardial infarction (7.9% vs 4.1%, p less than 0.05), required prolonged ventilatory support (7.9% vs 3.1%, NS), and had major neurologic complications (4.0% vs 1.1%, p less than 0.001). The mortality rate was significantly higher in the elderly patients (5.9% vs 1.9%, p less than 0.01) but did not correlate with degree of coronary artery disease, anginal pattern, or preoperative ventricular function. Only 2 of 12 deaths in the elderly patients were from cardiac causes. This data would suggest that elderly patients have an increased risk for significant cardiac and noncardiac morbidity and mortality following coronary artery bypass surgery and that the higher mortality rate in this age group may be a result of noncardiac organ failure.

Efficacy of percutaneous transluminal coronary angioplasty compared with single-vessel bypass

The use of percutaneous transluminal coronary angioplasty has been increasing rapidly. When the procedure is successful, the clinical relief of symptoms is similar to that achieved with direct coronary artery bypass. It has been suggested that the angioplasty procedure, however, can accomplish these results with potentially less morbidity and mortality, along with a shorter hospital stay. In order to evaluate the results of percutaneous transluminal coronary angioplasty with single-vessel coronary artery bypass, we performed a retrospective review. From January, 1982, to December, 1983, a total of 198 angioplasty procedures were performed. They were successful in 142 patients (71.7%). Emergency bypass was performed in 21 (10.6%) of the 56 patients who had undergone unsuccessful angioplasty procedures. Perioperative myocardial infarction occurred in eight of these patients (38.1%). There were no operative deaths, but there was one death after angioplasty. Elective bypass was performed in 28 of the patients who had angioplasty procedures, with no perioperative myocardial infarctions or operative deaths. Recurrent symptoms developed in 31 (21.8%) of the 142 patients who had undergone initially successful angioplasty. From 1982 to 1983, single-vessel bypass was performed in 143 patients. The internal mammary artery was utilized in 102 patients and the autogenous saphenous vein in 41 patients. There were no perioperative myocardial infarctions or deaths. No patients developed recurrent symptoms during the study interval. Percutaneous transluminal coronary angioplasty is an acceptable alternative to coronary artery bypass in patients with localized lesions that are sufficiently serious to cause symptoms and warrant surgical bypass. However, the angioplasty procedure, when compared to single-vessel coronary artery bypass, may result in an increased incidence of acute myocardial infarction and in a significantly (p less than 0.001) increased incidence of early recurrence of symptoms.

Paraplegia following percutaneous insertion of an intra-aortic balloon

Paraplegia following insertion of an intra-aortic balloon is an extremely rare and unusual complication with only one previous report in the literature. We recently encountered this problem in a man with severe coronary disease and unstable angina. The etiology of this complication, although never established in our patient, was most likely a critical occlusion of a spinal cord artery as a result of either a small dissection or an arterial embolus.

Use of profound hypothermia and circulatory arrest for the calcified aorta

This case report discusses one method of dealing with the extensively calcified aorta in patients undergoing open heart surgery. Profound hypothermia and circulatory arrest was used in a patient undergoing aortic valve replacement with severe calcification of the ascending aorta and transverse arch. This patient recovered from surgery and was discharged from the hospital with no neurologic deficits.