Ventilatory dependency after cardiovascular surgery

OBJECTIVES

Ventilatory dependency is a widely recognized complication of cardiovascular surgery, often leading to tracheostomy. Some risk factors for its occurrence have been documented. Less well characterized are short- and long-term outcomes. Therefore, objectives were to identify risk factors for ventilatory dependency, assess its short- and long-term outcomes, and determine impact of tracheostomy.

METHODS

From January 1998 to September 2001, 12,777 patients underwent cardiovascular surgery and survived at least 72 hours. Of these patients, 704 (5.5%) developed ventilatory dependency (cumulative intubation >72 hours); 185 (26%) underwent tracheostomy. Preoperative, intraoperative, and intensive care unit admission data were used sequentially to understand predictors of ventilatory dependency. Outcomes were analyzed by time-related methods, and impact of tracheostomy was assessed using competing-risks analysis.

RESULTS

Hemodynamic status on intensive care unit admission (low cardiac output, vasopressor use, pulmonary hypertension; P < .0001) and early postoperative events (stroke, bacteremia; P < .0001) were more important than preoperative and intraoperative variables in predicting ventilatory dependency. Survival at 30 days, 1 year, and 5 years thereafter was 76%, 49%, and 33% and was strongly associated with favorable hemodynamic status. By 28 days, 24% of patients received tracheostomy; survival at 30 days and 2 years thereafter was 74% and 26%, considerably below anticipated survivals of 84% and 58%.

CONCLUSIONS

Improved operative and postoperative strategies to preserve myocardial function and restore hemodynamics should decrease the prevalence of ventilatory dependency. Unfortunately, preoperative models of ventilatory dependency are too insensitive for clinical use. Tracheostomy and its outcome are also poorly predicted, highlighting the complex interaction of events altering patients' conditions before and after tracheostomy.

A Benchmark for Evaluating Innovative Treatment of Left Main Coronary Disease

BACKGROUND

Left main trunk stenosis (> or = 50%) has traditionally been treated with coronary artery bypass grafting. Improvements in coronary stents have led some to advocate percutaneous coronary intervention. To provide a benchmark of outcomes against which percutaneous coronary intervention may be compared, we (1) assessed survival and freedom from coronary reintervention after coronary artery bypass grafting in these patients and (2) identified their risk factors.

METHODS AND RESULTS

From 1971 to 1998, the first 1000 primary coronary artery bypass grafting patients (n=26,927) were followed every 5 years. Of these, 3803 had left main trunk stenosis > or = 50%. A multivariable, nonproportional hazards, time-related analysis was performed to model survival and freedom from coronary reintervention (percutaneous coronary intervention or reoperation) and to identify their risk factors. Survival at 30 days, 1, 5, 10, 15, and 20 years was 97.6%, 93.6%, 83%, 64%, 44%, and 28%, respectively, and freedom from coronary reintervention was 99.7%, 98.9%, 96.6%, 89%, 76%, and 61%, respectively. Worse left ventricular function (P<0.0001), diabetes (P<0.0001), hypertension (P<0.001), peripheral arterial disease (P=0.0002), smoking (P<0.0001), and elevated triglycerides (P=0.01) decreased survival, and younger age (P<0.0001), elevated triglycerides (P=0.005), and incomplete revascularization (P=0.003) increased coronary reintervention. Internal thoracic artery grafting of the left anterior descending improved survival and decreased coronary reintervention.

CONCLUSIONS

This study provides a 20-year outcome benchmark for surgical treatment of left main trunk disease. It indicates that simple comparisons of new treatments are inadequate without risk adjustment. Risk factor adjustment should be used when comparing coronary artery bypass grafting with current and future treatment innovations and when selecting the best treatment strategy for individual patients.

Does right thoracotomy increase the risk of mitral valve reoperation?

OBJECTIVE

The study objective was to determine whether a right thoracotomy approach increases the risk of mitral valve reoperation.

METHODS

Between January of 1993 and January of 2004, 2469 patients with mitral valve disease underwent 2570 reoperations (1508 replacements, 1062 repairs). The approach was median sternotomy in 2444 patients, right thoracotomy in 80 patients, and other in 46 patients. Multivariable logistic regression was used to identify factors associated with median sternotomy versus right thoracotomy, mitral valve repair versus replacement, hospital death, and stroke. Factors favoring median sternotomy (P < .03) included coronary artery bypass grafting (30% vs 2%), aortic valve replacement (39% vs 2%), tricuspid valve repair (27% vs 13%), fewer previous cardiac operations, more recent reoperation, and no prior left internal thoracic artery graft. These factors were used to construct a propensity score for risk-adjusting outcomes.

RESULTS

Hospital mortality was 6.7% (163/2444) for the median sternotomy approach and 6.3% (5/80) for the thoracotomy approach (P = .9). Risk factors (P < .04) included earlier surgery date, higher New York Heart Association class, emergency operation, multiple reoperations, and mitral valve replacement. Stroke occurred in 66 patients (2.7%) who underwent a median sternotomy and in 6 patients (7.5%) who underwent a thoracotomy (P = .006). Mitral valve replacement (vs repair) was more common in those receiving a thoracotomy (P < .04).

CONCLUSIONS

Compared with median sternotomy, right thoracotomy is associated with a higher occurrence of stroke and less frequent mitral valve repair. Specific strategies for conducting the operation should be used to reduce the risk of stroke when right thoracotomy is used for mitral valve reoperation. In most instances, repeat median sternotomy, with its better exposure and greater latitude for concomitant procedures, is preferred.

Reoperation After Mitral Valve Repair for Degenerative Disease

BACKGROUND

With recent increases in frequency of mitral valve repair for degenerative disease, surgeons will encounter more patients with recurrent mitral regurgitation after repair. Objectives of this study were to determine (1) mechanisms for and timing of failed repair of degenerative disease and approach to reoperation, (2) durability of re-repair, and (3) long-term survival after reoperation.

METHODS

From January 1980 to January 2005, 188 patients underwent reoperation for recurrent mitral regurgitation. Follow-up averaged 6.5 +/- 5.0 years.

RESULTS

Mechanisms of failure were procedure related in 71 patients, valve related in 84, both in 25, or uncertain in 8. Intervention was early (median, 19 days) for procedure-related failure and later (median, 5.4 years) for valve-related failure (p < 0.0001). Procedure-related failure was caused by suture dehiscence in 40 (42%) of 96 patients, rupture of previously shortened chordae in 20 (21%), systolic anterior motion in 20 (21%), hemolysis in 21 (22%), and incomplete initial correction in 11 (11%). Valve-related failure was caused by progressive disease in 100 (92%) of 109 patients and endocarditis in 11 (10%); these were not mutually exclusive. Mitral valve replacement was performed in 64% and re-repair in 36% (65% of recent reoperations). Freedom from a second mitral reoperation after re-repair was 93% at 10 years. Survival at 1, 5, and 10 years was 88%, 81%, and 62%, respectively.

CONCLUSIONS

When reoperation occurs late after repair of degenerative mitral valve disease, new valve pathology is usually the culprit, and re-repair is less common. In contrast, reoperation for procedure-related failure occurs early and is often amenable to re-repair. When performed, valve re-repair is durable.

Endovascular treatment of thoracoabdominal aortic aneurysms

OBJECTIVE

To establish the safety and efficacy of endovascular repair of thoracoabdominal aortic aneurysms.

METHODS

Between May 2004 and February 2006, patients with thoracoabdominal aneurysms considered high risk for conventional surgery were enrolled in a prospective trial to evaluate a novel endovascular grafting system. Devices were custom designed for each patient using high-resolution computed tomography. Patient data included mortality, morbidity, procedural details, and surrogate end points for endovascular repair. These were collected at hospital discharge and at 1, 6, and 12 months.

RESULTS

Seventy-three patients underwent endovascular repair of thoracoabdominal aortic aneurysms for type I, II, or III (n = 28), or for type IV (n = 45) thoracoabdominal aneurysms. Mean aneurysm size was 7.1 cm (range 4.5-11.3 cm). General anesthesia was used in 47% of patients and regional anesthesia in 53%. There were no conversions to open surgery nor ruptures post-treatment. Technical success was achieved in 93% of patients (68/73). Thirty-day mortality was 5.5% (4/73). Major perioperative complications occurred in 11 (14%) patients and included paraplegia (2.7%, 2/73), new onset of dialysis (1.4%, 1/73), prolonged ventilator support (6.8%, 5/73), myocardial infarction (5.5%, 4/73), and minor hemorrhagic stroke (1.4%; 1/72). A majority of patients had no complications. Mean length of stay was 8.6 days. At follow-up, 6 deaths had occurred. There were no instances of stent migration nor aneurysmal growth.

CONCLUSIONS

Endovascular repair of aortic aneurysms involving the visceral segment in nonsurgical candidates is feasible. Known complications of repair are not eliminated, but morbidity and mortality appeared low relative to the high-risk population studied. Further refinement of device design, delivery technique, and patient selection is ongoing. Assessment of durability will require longer follow-up.

Impact of mitral valve annuloplasty combined with revascularization in patients with functional ischemic mitral regurgitation

OBJECTIVES

The aim of this work was to determine whether mitral valve (MV) annuloplasty benefits patients with moderate/severe (3+/4+) functional ischemic mitral regurgitation (MR) who undergo coronary artery bypass grafting (CABG).

BACKGROUND

Mitral regurgitation is a strong predictor of poor outcomes in patients with ischemic cardiomyopathy; whether correcting it at the time of CABG improves outcomes is less certain.

METHODS

From 1991 to 2003, 390 patients with 3+/4+ ischemic MR had CABG with (n = 290) or without (n = 100) MV annuloplasty. Groups were propensity-matched using demographics, extent of coronary disease, regional wall motion, and quantitative electrocardiography. Survival, echocardiographic severity of MR, and New York Heart Association (NYHA) functional class were compared.

RESULTS

One-, 5-, and 10-year survival was 88%, 75%, and 47% after CABG alone and 92%, 74%, and 39% after CABG + MV annuloplasty (p = 0.6). Mortality was increased in patients with severe lateral wall motion abnormalities (p = 0.05), ST-segment elevation in lateral leads (p < 0.004), and higher QRS voltage sum (p < 0.0001). Patients undergoing CABG alone were more likely to have 3+/4+ postoperative MR than those undergoing CABG + MV annuloplasty (48% vs. 12% at 1 year, p < 0.0001). The NYHA functional class substantially improved in both groups (p < 0.001) and remained improved; at 5 years, 23% of patients having CABG + mitral annuloplasty and 25% having CABG alone were in NYHA functional class III/IV.

CONCLUSIONS

Although CABG + MV annuloplasty reduces postoperative MR and improves early symptoms compared with CABG alone, it does not improve long-term functional status or survival in patients with severe functional ischemic MR. The MV annuloplasty in this setting, without addressing fundamental ventricular pathology, is insufficient to improve long-term clinical outcomes.

Acute in vivo evaluation of a new stentless mitral valve

OBJECTIVES

We have developed a stentless pericardial mitral valve prosthesis in 2 configurations; the purposes of this acute study in sheep were to assess (1) valve design and implant technique; (2) valve performance; and (3) acute effects on postimplant left ventricular function.

METHODS

A stentless bovine pericardial bileaflet valve was developed with the intent to preserve annular-papillary muscle continuity. This valve, in 2 configurations-with (n = 5) and without (n = 5) flap chordae-was implanted in 10 sheep (mean weight 73 +/- 9 kg). Epicardial echocardiography was performed to assess valve performance. Load-independent left ventricular function was also estimated before implantation (baseline), 1 hour after discontinuing cardiopulmonary bypass (rest), and during dobutamine stimulation using conductance technology.

RESULTS

Implantation was easily accomplished for both configurations. Both configurations had low transvalvular pressure (mean 2.1 +/- 1.2 mm Hg at rest; 2.2 +/- 1.0 mm Hg with dobutamine stimulation with flap chordae; 1.7 +/- 0.5 mm Hg and 1.6 +/- 0.3 mm Hg without flap chordae). No mitral regurgitation was observed in 8 sheep, and mild regurgitation was seen in 2 sheep. Compared with baseline, slope of maximum rate of change of left ventricular pressure-end-diastolic volume relation increased with stimulation both with flap chordae (+52 +/- 41 mm Hg x s(-1)x mL(-1), P = .0005) and without (+20 +/- 12 mm Hg x s(-1) x mL(-1), P = .003).

CONCLUSIONS

Both configurations of this newly designed stentless mitral bioprosthesis, which preserves annular-papillary muscle continuity using different novel surgical implantation techniques, demonstrated reliable valve performance, with low transvalvular pressure gradients, minimal regurgitation, and acutely preserved postimplant left ventricular function. Further chronic study is needed to verify these results and evaluate reliability of implantation procedures, biocompatibility, and durability.

Surgical treatment of postinfarction left ventricular pseudoaneurysm

BACKGROUND

Left ventricular pseudoaneurysm from myocardial infarction is rare and is associated with a high risk of rapid enlargement and rupture. The purposes of this study were to describe its clinical presentation, assess the accuracy of diagnostic imaging modalities, and determine operative and late surgical results.

METHODS

From January 1986 through December 2001, 30 patients aged 50 to 85 years (mean, 68; 70% male) underwent left ventricular pseudoaneurysm repair. Two surgical approaches were used: primary repair (n = 5, 17%) and patch closure (n = 25, 83%). Twenty-one patients (70%) had concomitant procedures, including coronary revascularization (n = 17, 57%) and mitral valve surgery (n = 9, 30%); 8 patients (29%) underwent emergent surgery. Clinical presentation, preoperative imaging data, and surgical outcomes were abstracted from medical records or obtained by patient follow-up.

RESULTS

The most common clinical presentations were heart failure (n = 22, 73%) and angina (n = 11, 41%). Pseudoaneurysm was rarely suspected at clinical presentation. Contrast ventriculography was diagnostic in 54% of patients in whom it was performed, as opposed to 97% for two-dimensional echocardiography (p = 0.2). Postoperative intra-aortic balloon pump was required in 7 patients (23%). Hospital mortality was 20%, and late survival was 73%, 59%, and 45% at 1, 5, and 8 years, respectively.

CONCLUSIONS

Left ventricular pseudoaneurysm should be suspected in postinfarction patients with unexplained heart failure. Echocardiography is usually diagnostic and is superior to ventriculography. The surgical mortality rate is elevated in this complex patient population. Long-term survival is also poor, mainly because of underlying ischemic cardiomyopathy.

Are Marfan Syndrome and Marfanoid Patients Distinguishable on Long-Term Follow-Up?

BACKGROUND

It is unclear whether late outcome differs for Marfan syndrome and marfanoid patients. Thus, we compared characteristics of Marfan versus marfanoid patients and their survival and requirement for reoperation.

METHODS

From 1978 to October 2003, 162 patients with a presumptive diagnosis of Marfan syndrome underwent operation. We recategorized them as confirmed Marfan (n = 122), marfanoid (n = 23), Ehlers-Danlos syndrome (n = 5), or other (n = 12). Patients categorized as marfanoid failed to meet the major criteria of Marfan syndrome. We compared characteristics of Marfan and marfanoid groups and assessed long-term survival and need for reoperation.

RESULTS

Marfan and marfanoid patients had similar demographics (women, 33% versus 39%; age, 39 +/- 13 versus 41 +/- 12 years; height, 186 +/- 12 cm versus 184 +/- 9.6 cm), valve pathophysiology (aortic regurgitation, 66% versus 58%; mitral regurgitation, 58% versus 62%), and aortic pathology (dilated, 40% versus 39%; dissected, 17% versus 13%). Overall hospital survival was 99.3% (144/145), and 10-year survival was similar at 82% in the Marfan and 100% in marfanoid groups (p = 0.13). Patients with aortic dissection (p = 0.001) and mitral valve replacement (p = 0.003) were at higher risk of death. Reoperation was more frequent after separate aortic valve-ascending aorta graft operations (p = 0.04), and among taller patients (p = 0.005). Of 24 Marfan patients with David root reimplantations, none has required reoperation.

CONCLUSIONS

Marfan and marfanoid patients have similar physical characteristics and postoperative survival, although reoperation was more frequent in Marfan patients. Surgery before occurrence of aortic dissection or mitral valve repair should reduce the risk of reoperation, but taller patients, irrespective of Marfan or gender, are more likely to require reoperation.

Technical challenges and complications of double valve replacement in the presence of small aortic and mitral annuli

A 57 year old female with rheumatic heart disease affecting both aortic and mitral valves underwent double valve replacement. The presence of small aortic and mitral annuli contributed to a series of intraoperative complications: left coronary ostium occlusion and type III atrioventricular groove disruption. The latter was repaired with a generous fresh autologous pericardial double layer patch and implant of a bileaflet mechanical prosthesis over the patch. Postoperatively, the patient developed prolonged respiratory insufficiency and pneumonia, transient myocardial dysfunction and acute renal failure. She was eventually discharged home without residual defects.

Cardiac surgery after mediastinal radiation: extent of exposure influences outcome

OBJECTIVES

Mediastinal radiation for thoracic malignancies uses multiple treatment fields and doses. We investigated whether more extensive radiation exposure is associated with more hospital complications and worse survival after cardiac surgery.

METHODS

From January 2000 to January 2005, 230 patients underwent cardiac surgery after 3 levels of mediastinal radiation: extensive (Hodgkin disease, thymoma, and testicular cancer; n = 70), variable (eg, non-Hodgkin lymphoma and lung cancer; n = 35); and tangential (breast cancer; n = 125). Hospital complications were recorded prospectively, and time-related survival was assessed by patient follow-up (mean follow-up, 2.2 +/- 1.4 years).

RESULTS

Patients receiving extensive exposure were youngest (51 vs 64 vs 72 years), with the longest radiation-to-operation interval (25 vs 13 vs 14 years), and had the most diastolic dysfunction, left main stenosis of greater than 70% (21% vs 9% vs 8%), and aortic regurgitation (79% vs 54% vs 50%). Patients receiving extensive and variable exposure had the poorest pulmonary function (percent predicted forced expiratory volume in 1 second, 57% vs 54% vs 67%; percent predicted forced vital capacity, 56% vs 63% vs 66%). All groups received a similar mix of cardiac procedures. Hospital deaths (13% vs 8.6% vs 2.4%) and respiratory complications (24% vs 20% vs 9.6%) were higher after more extensive radiation, and survival was poorer (4-year survival, 64% vs 57% vs 80%) than for patients receiving tangential radiation exposure, and it deviated more from expected matched-population life tables.

CONCLUSIONS

Among patients undergoing cardiac surgery after thoracic radiation, radiation exposure is heterogeneous, and therefore these patients cannot be managed and assessed as a single uniform cohort. Extensively irradiated patients are more likely to develop radiation heart disease, which increases perioperative morbidity and decreases short- and long-term survival.

Folding Valvuloplasty Without Leaflet Resection: Simplified Method for Mitral Valve Repair

Standard repair techniques can prove challenging in patients with severe myxomatous mitral valve disease when there is a broad-based mid-portion of the posterior leaflet and small medial and lateral scallops. We describe a new surgical technique in which the mitral valve repair was accomplished by simple folding the prolapsed segment of the posterior leaflet and by insertion of the flexible annuloplasty ring.

The impact of left ventricular reconstruction on survival in patients with ischemic cardiomyopathy

OBJECTIVE

Left ventricular reconstruction (LVR) is performed to improve the morphologic structure and function of the heart in patients with heart failure. This procedure has been performed at the Cleveland Clinic Foundation since 1997. We assessed mortality, functional status, and predictors of outcome in these patients.

METHODS

Data were extracted from multiple prospectively acquired datasets on demographic, clinical, and operative details of 220 consecutive patients who underwent LVR between July 1997 and July 2003, where the indication for surgery was heart failure (of whom 66% had New York Heart Association (NYHA) functional class III or IV symptoms). Mortality, functional status, and postoperative complications were ascertained by reference to the clinical record, social security death index, and by phone contact. Mean preoperative left ventricular ejection fraction (LVEF) was 21.5+/-7.3% and mean left ventricular end-diastolic diameter was 6.4+/-1.0 cm. The mean age was 61.4+/-9.0 years and 80% were male. The majority (86%) of patients underwent concomitant coronary artery bypass grafting and 49% underwent mitral valve surgery.

RESULTS

Thirty-day mortality was 1% and survival at 1, 3, and 5 years was 92%, 90%, and 80%, respectively. Of the survivors for whom data on NYHA functional class were available, 85% were in NYHA functional class I or II. Mortality was predicted by reduced preoperative ejection fraction <20% (unadjusted hazard ratio 1.53, p = 0.02), body mass index < or = 24 kg/m2 (unadjusted hazard ratio 1.69, p = 0.01), QRS duration > or = 130 ms (unadjusted hazard ratio 1.66, p = 0.01) and the requirement for renal replacement therapy postoperatively (unadjusted hazard ratio 3.85, p < 0.01). Mean LVEF improved to 24.7+/-8.86% (p < 0.01) and left ventricular volumes were also significantly reduced.

CONCLUSIONS

In selected patients with heart failure, LVR, in conjunction with revascularization and valve surgery, is associated with excellent survival, improved symptoms, and improved LVEF and left ventricular dimensions.

Surgical treatment of pseudoaneurysm of the thoracic aorta

OBJECTIVES

To examine the clinical profiles, operative outcomes, and late results of patients with pseudoaneurysm of the thoracic aorta.

METHODS

From 1990 to 2002, 60 patients underwent repair of aortic pseudoaneurysm: ascending aorta in 70%, ascending aorta and arch in 15%, descending aorta in 10%, and arch alone in 5%. Mean age was 53 +/- 15 years, and 70% were men. Of these, 50 (83%) had undergone previous cardiac surgery, including 22 (37%) composite valve graft operations. The preferred cannulation site was femoral-femoral (n = 27, 45%), with deep hypothermic circulatory arrest in 62% and retrograde cerebral perfusion in 33%; more recently, however, axillary cannulation has been preferred.

RESULTS

Principal etiologies were graft infection in ascending aorta pseudoaneurysm and trauma in descending aorta pseudoaneurysm. Fifteen patients (25%) presented with chest pain, 13 (22%) with heart failure, and 20% with moderate or severe aortic regurgitation. The pseudoaneurysm was resected and the aorta replaced (n = 45, 75%) or repaired (n = 15, 25%) using various methods. Hospital mortality was 6.7% (n = 4). Reexploration for bleeding was required in 8.3%, and 3.3% had postoperative stroke. At 30 days, 5 years, and 10 years, survival was 94%, 74%, and 60% and freedom from reoperation was 95%, 77%, and 67%, respectively.

CONCLUSIONS

Most patients with aortic pseudoaneurysm require ascending aorta and/or arch replacement, which can be accomplished with low operative mortality and morbidity. Long-term survival and freedom from reoperation in these young patients parallel those expected for complex cardiac and aortic disease.

Occurrence and Risk Factors for Reintervention After Coronary Artery Bypass Grafting

BACKGROUND

Reintervention after coronary artery bypass grafting (CABG) is common. We sought to determine its occurrence and identify patient characteristics and operative techniques that influence the need or bias for reintervention.

METHODS AND RESULTS

From 1971 to 1998, 48,758 patients underwent primary isolated CABG, and 1000 patients per year were actively followed-up every 5 years (n =26,927). A multivariable time-related analysis was performed to model freedom from first coronary reintervention (either reoperation or percutaneous coronary intervention) and identify patient and operative characteristics associated with first reintervention. A total of 3997 patients underwent coronary reintervention, percutaneous in 1638 and reoperation in 2359. Freedom from reintervention was 99%, 96%, 88%, 73%, 60%, and 46% at 1, 5, 10, 15, 20, and 25 years, respectively. Risk of reintervention (hazard function) demonstrated a short, rapidly declining early phase followed by a longer, slow-rising late phase. Patient variables increasing the likelihood of coronary reintervention included younger age (P<0.0001), higher triglycerides (P=0.002), lower high-density lipoprotein (P=0.006), diabetes mellitus (P<0.0001), and more extensive coronary artery disease (P=0.0005). Increasing extent of arterial grafting performed at primary operation decreased the likelihood of coronary reintervention (P<0.0001).

CONCLUSIONS

Reintervention after primary CABG is common. Risk factors for arteriosclerosis and type of bypass conduit influence the need or bias for repeat coronary therapy. Aggressive post-CABG risk factor reduction and extensive arterial grafting at primary operation should decrease coronary reinterventions.