An Unusual Cause of Acute Abdominal Pain and Unexplained Dyspnea in a Young Man: A Sinus of Valsalva Aneurysm

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SVA is due to weakness of the elastic lamina.

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Rupture can lead to right ventricular and right atrial fistulas.

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TTE is the first-line imaging modality due to portability, convenience, and accuracy.

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Nonstandard views with sweeps are important to define pathologic communications.

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TEE is the modality of choice for structural intervention and surgical planning.

Redo-aortic valve replacement in prior stentless prosthetic aortic valves: Transcatheter versus surgical approach

OBJECTIVES

The objective was to compare outcomes of redo-aortic valve replacement (AVR) via surgical or transcatheter approach in prior surgical AVR with large percentage of prior stentless surgical AVR.

BACKGROUND

With the introduction of transcatheter aortic valve replacement (TAVR), patients with increased surgical risks now have an alternative to redo surgical AVR (SAVR), known as valve-in-valve (ViV) TAVR. Stentless prosthetic aortic valves present a more challenging implantation for ViV-TAVR given the lack of structural frame.

METHODS

We performed a retrospective study of 173 subjects who have undergone SAVR (N = 100) or ViV-TAVR (N = 73) in patients with prior surgical AVR at Wake Forest Baptist Medical Center from 2009 to 2019. Our study received the proper ethical oversight.

RESULTS

The average ages in redo-SAVR and ViV-TAVR groups were 58.03 ± 13.86 and 66.57 ± 13.44 years, respectively (p < 0.0001). The redo-SAVR had significantly lower STS (2.78 ± 2.09 and 4.68 ± 5.51, p < 0.01) and Euroscores (4.32 ± 2.98 and 7.51 ± 8.24, p < 0.05). The redo-SAVR group had higher percentage requiring mechanical support (8% vs. 0%, p < 0.05) and vasopressors (53% vs. 0%, p < 0.0001), longer length of stay (13.65 ± 11.23 vs. 5.68 ± 7.64 days, p < 0.0001), and inpatient mortality (16% vs. 2.78%, p < 0.005). At 30-day follow-up, redo-SAVR group had higher rates of acute kidney injury (10% vs. 0%, p < 0.01), however ViV-TAVR group had more new left bundle branch blocks (6.85% vs. 0%, p < 0.05). No significant differences regarding re-hospitalization rates, stroke, or death up to 1-year.

CONCLUSION

Although the ViV-TAVR group had higher risk patients, there were significantly fewer procedural complications, shorter length of stay, and similar mortality outcomes up to 1-year follow-up.

Echocardiography and EuroSCORE II for the stratification of low-gradient severe aortic stenosis and preserved left ventricular ejection fraction

The purpose of this study was to explore the utility of echocardiography and the EuroSCORE II in stratifying patients with low-gradient severe aortic stenosis (LG SAS) and preserved left ventricular ejection fraction (LVEF ≥ 50%) with or without aortic valve intervention (AVI). The study included 323 patients with LG SAS (aortic valve area ≤ 1.0 cm² and mean pressure gradient < 40 mmHg). Patients were divided into two groups: a high-risk group (EuroSCORE II ≥ 4%, n = 115) and a low-risk group (EuroSCORE II < 4%, n = 208). Echocardiographic and clinical characteristics were analyzed. All-cause mortality was used as a clinical outcome during mean follow-up of 2 ± 1.3 years. Two-year cumulative survival was significantly lower in the high-risk group than the low-risk patients (62.3% vs. 81.7%, p = 0.001). AVI tended to reduce mortality in the high-risk patients (70% vs. 59%; p = 0.065). It did not significantly reduce mortality in the low-risk patients (82.8% with AVI vs. 81.2%, p = 0.68). Multivariable analysis identified heart failure, renal dysfunction and stroke volume index (SVi) as independent predictors for mortality. The study suggested that individualization of AVI based on risk stratification could be considered in a patient with LG SAS and preserved LVEF.

Thoracoscopic resection of left atrial appendage aneurysm in a 16-year-old boy

We report a case of a left atrial appendage aneurysm (LAAA) in a 16-year-old boy presenting with supraventricular tachycardia (SVT). The aneurysm was detected incidentally on a routine echocardiogram performed prior to electrophysiology (EP) study for evaluation and management of the SVT. The aneurysm was successfully resected under cardiopulmonary bypass (CPB) via video-assisted thoracoscopic surgery (VATS). VATS is a useful approach for LAAA in the pediatric population.

Assessment of the prognostic significance of low gradient severe aortic stenosis and preserved left ventricular function requires the integration of the consistency of stroke volume calculation and clinical data

BACKGROUND

This study was to evaluate the prognostic significance of low gradient severe aortic stenosis (LG SAS) and preserved left ventricular ejection fraction (LVEF) with the integration of echocardiographic and clinical data.

METHODS

The study included 172 patients with LG SAS (AVAi ≤ 0.6 cm² /m² , mean aortic pressure gradient < 40 mm Hg) and LVEF (≥ 50%). LV outflow tract diameters were measured at both the aortic valve annulus and 5 mm below the annulus for the measurement consistency. Patients were divided into the low flow LG SAS (LF/LG SAS: SVi < 35mL/m² and AVAi ≤ 0.6 cm² /m² ) and normal-flow LG SAS groups (NF/LG SAS: SVi ≥ 35mL/m² and AVAi ≤ 0.6 cm² /m² ). Echocardiographic findings and clinical data were systematically analyzed with mean follow-up of 3.0 ± 1.6 years.

RESULTS

LF/LG SAS had significantly smaller AVAi, lower SVi, a higher prevalence of atrial fibrillation (28% vs 12% P = .01) and diabetes (47% vs 27% P = .007) and lower 3-year cumulative survival than NF/LG SAS. Multivariable analysis showed that dyspnea, renal dysfunction (CI 1.42-3.99, P < .01), left atrial diameter, and SVi were independently associated with an increased risk for all-cause mortality. Aortic valve intervention (AVI) improved survival in LF/LG SAS (68% vs 48%, P < .05) in comparison with medical management (HR: 4.20, CI: 1.12-15.76, P = .03), but only modestly in NF/LG SAS (75% vs 65% P > .05).

CONCLUSION

Outcome of LG SAS was independently associated with clinical characteristics. AVI likely improved outcome of LF/LG SAS who had high-risk clinical characteristics and unfavorable echocardiographic findings.

Whole-Genome and Segmental Homozygosity Confirm Errors in Meiosis as Etiology of Struma Ovarii

Strumae ovarii are neoplasms composed of normal-appearing thyroid tissue that occur within the ovary and rarely spread to extraovarian sites. A unique case of struma ovarii with widespread dissemination detected 48 years after removal of a pelvic dermoid provided the opportunity to reexamine the molecular nature of this form of neoplasm. One tumor, from the heart, consisting of benign thyroid tissue was found to have whole-genome homozygosity. Another tumor from the right mandible composed of malignant-appearing thyroid tissue showed whole-genome homozygosity and a deletion of 7p, presumably the second hit that transformed it into a cancerous tumor. Specimens from 2 other cases of extraovarian struma confined to the abdomen and 8 of 9 cases of intraovarian struma showed genome-wide segmental homozygosity. These findings confirm errors in meiosis as the origin of struma ovarii. The histological and molecular findings further demonstrate that even when outside the ovary, strumae ovarii can behave nonaggressively until they receive a second hit, thereafter behaving like cancer.

A comparison of valve-in-valve transcatheter aortic valve replacement in failed stentless versus stented surgical bioprosthetic aortic valves

Objectives

The objectives of this study were to compare short‐ and intermediate‐term clinical outcomes, procedural complications, TAVR prosthesis hemodynamics, and paravalvular leak (PVL) in stentless and stented groups.

Background

Valve‐in‐valve (ViV) transcatheter aortic valve replacement (TAVR) is an alternative to surgical redo for bioprosthetic valve failure. There have been limited data on ViV in stentless surgical valves.

Methods

We retrospectively analyzed 40 patients who underwent ViV TAVR in prior surgical bioprosthetic valves at Wake Forest Baptist Medical Center from October 2014 to September 2017. Eighty percent (32/40) ViV TAVRs were in stentless, while 20% (8/40) were in stented bioprosthetic valves.

Results

The primary mode of bioprosthetic valve failure for ViV implantation in the stentless group was aortic insufficiency (78%, 25/32), while in the stented group was aortic stenosis (75%, 6/8). The ViV procedure success was 96.9% (31/32) in stentless group and 100% in stented group (8/8). There were no significant differences in all‐cause mortality at 30 days between stentless and stented groups (6.9%, 2/31 versus 0%, 0/8, P = 0.33) and at 1 year (0%, 0/25 versus 0%, 0/5). In the stentless group, 34.4% (11/32) required a second valve compared to the stented group of 0% (0/8). There was a significant difference in the mean aortic gradient at 30‐day follow‐up (12.33 ± 6.33 mmHg and 22.63 ± 8.45 mmHg in stentless and stented groups, P < 0.05) and at 6‐month follow‐up (9.75 ± 5.07 mmHg and 24.00 ± 11.28 mmHg, P < 0.05), respectively.

Conclusions

ViV in the stentless bioprosthetic aortic valve has excellent procedural success and intermediate‐term results. Our study shows promising data that may support the application of TAVR in stentless surgical aortic valve. However, further and larger studies need to further validate our single center's experience.

Effect of a dexmedetomidine substitution during a nationwide propofol shortage in patients undergoing coronary artery bypass graft surgery

STUDY OBJECTIVE

To assess the effect of substituting dexmedetomidine for propofol during a nationwide propofol shortage on postoperative time to extubation and opioid requirements in patients who underwent coronary artery bypass graft (CABG) surgery.

DESIGN

Retrospective case-control study.

SETTING

Single-center cardiothoracic intensive care unit (ICU) in a tertiary academic medical center.

PATIENTS

Seventy adults undergoing isolated, primary, elective CABG who received dexmedetomidine between April 1 and June 30, 2010, during the propofol shortage (35 patients [cases]) or who received propofol between January 1 and March 31, 2010, or between July 1 and September 30, 2010 (35 patients [controls]) for postoperative sedation were included. Patients in the dexmedetomidine group were matched 1:1 to patients in the propofol group based on age, sex, weight, number of vessels bypassed, preoperative ejection fraction, cardiopulmonary bypass time, and aortic cross-clamp time.

MEASUREMENTS AND MAIN RESULTS

The primary outcome consisted of opioid requirements in the first 12 hours after arrival to the ICU in the dexmedetomidine- and propofol-treated patients. Secondary outcomes included the time to extubation (from ICU admission until extubation) and opioid requirements in the first 24 hours. No significant demographic differences were noted between treatment groups. Median opioid requirements in the first 12 hours, as measured by morphine equivalents, were 8.0 mg in the propofol group and 7.0 mg in the dexmedetomidine group (p=0.1). Similarly, at 24 hours, opioid requirements were 16.7 and 17.3 mg in the propofol and dexmedetomidine groups, respectively (p=0.4). The time to extubation demonstrated that patients in the propofol group were extubated at a median of 300 minutes and patients in the dexmedetomidine group were extubated at a median of 318 minutes after ICU arrival (p=0.5).

CONCLUSION

No statistically significant differences were noted between the propofol and dexmedetomidine groups when assessing the outcomes of opioid requirements and the time to extubation. A multicenter, prospective, randomized, blinded study is needed to determine the optimal sedative after CABG surgery.

Cannula design reduces particulate and gaseous emboli during cardiopulmonary bypass for coronary revascularization

Purpose: The incidence of neurocognitive deficits after coronary bypass surgery remains problematic, with atheroembolism being one of the major causes. External manipulation of aorta and the “sandblasting” effect of the high-velocity perfusion jet can cause dislodgement of atheromatous debris.

Description: A new arterial cannula features a tip configuration that diffuses the flow through multiple outlets, providing reduced velocity and shear with one central and three diverted flow streams.

Evaluation: Between March 2007 and July 2008 twenty patients having isolated coronary artery bypass operations were instrumented with an Embolus Detection and Classification transducer. These data were compared to 43 patients from a previous study using similar techniques except for a standard open-tip arterial cannula. Total embolic counts were markedly lower in the new cannula group (20±25 vs 174±378) as were both gaseous (11±15 vs 95±211) and particulate counts (9±11 vs 80±194).

Conclusions: The select 3D cannula design reduces the sandblasting effect of the perfusion jet and, also, may direct emboli from the heart and cardiopulmonary bypass equipment away from the cerebral circulation.

Prognostic value of tissue Doppler-Derived E/e' on early morbid events after cardiac surgery

BACKGROUND

The tissue Doppler-derived surrogate for left ventricular diastolic pressure, E/e', has been used to prognosticate outcome in a variety of cardiovascular conditions. In this study, we determined the relationship of intraoperative E/e' to the use of inotropic support, duration of mechanical ventilation (MV), length of intensive care unit stay (ICU-LOS), and total hospital stay (H-LOS) in patients requiring cardiac surgery. The records of 245 consecutive patients were retrospectively reviewed to obtain 205 patients who had intraoperative transesophageal echocardiography examinations prior to coronary artery bypass grafting and/or valvular surgery. Cox proportional hazards and logistic regression models were used to analyze the relation between intraoperative E/e' or LVEF and early postoperative morbidity (H-LOS, ICU-LOS, and MV) and the probability that a patient would require inotropic support. With adjustments for other predictors (female gender, hypertension, diabetes, history of myocardial infarction, emergency surgery, renal failure, procedure type, and length of aortic cross-clamp time), an elevated E/e' ratio (>or=8) was significantly associated with an increased ICU-LOS (49 versus 41 median h, P = 0.037) and need for inotropic support (P = 0.002) while baseline LVEF was associated with inotropic support alone (P < 0.0001). These data suggest that the tissue Doppler-derived index of left ventricular diastolic filling pressure may be a useful indicator for predicting early morbid events after cardiac surgery, and may even provide additional information from that of baseline LVEF. Further, patients with elevated preoperative E/e' may need more careful peri- and postoperative management than those patients with E/e' <8.

Nosocomial pneumonia risk and stress ulcer prophylaxis: a comparison of pantoprazole vs ranitidine in cardiothoracic surgery patients

BACKGROUND

Stress ulcer prophylaxis (SUP) using ranitidine, a histamine H2 receptor antagonist, has been associated with an increased risk of ventilator-associated pneumonia. The proton pump inhibitor (PPI) pantoprazole is also commonly used for SUP. PPI use has been linked to an increased risk of community-acquired pneumonia. The objective of this study was to determine whether SUP with pantoprazole increases pneumonia risk compared with ranitidine in critically ill patients.

METHODS

The cardiothoracic surgery database at our institution was used to identify retrospectively all patients who had received SUP with pantoprazole or ranitidine, without crossover between agents. From January 1, 2004, to March 31, 2007, 887 patients were identified, with 53 patients excluded (pantoprazole, 30 patients; ranitidine, 23 patients). Our analysis compared the incidence of nosocomial pneumonia in 377 patients who received pantoprazole with 457 patients who received ranitidine.

RESULTS

Nosocomial pneumonia developed in 35 of the 377 patients (9.3%) who received pantoprazole, compared with 7 of the 457 patients (1.5%) who received ranitidine (odds ratio [OR], 6.6; 95% confidence interval [CI], 2.9 to 14.9). Twenty-three covariates were used to estimate the probability of receiving pantoprazole as measured by propensity score (C-index, 0.77). Using this score, pantoprazole and ranitidine patients were stratified according to their probability of receiving pantoprazole. After propensity adjusted, multivariable logistic regression, pantoprazole treatment was found to be an independent risk factor for nosocomial pneumonia (OR, 2.7; 95% CI, 1.1 to 6.7; p = 0.034).

CONCLUSION

The use of pantoprazole for SUP was associated with a higher risk of nosocomial pneumonia compared with ranitidine. This relationship warrants further study in a randomized controlled trial.

Effects of a waiting period after clopidogrel treatment before performing coronary artery bypass grafting

STUDY OBJECTIVE

To assess the effects of a waiting period after clopidogrel treatment before coronary artery bypass grafting (CABG). Design. Single-center, prospective, observational study.

SETTING

Cardiothoracic surgery intensive care unit at a university-affiliated medical center.

PATIENTS

One hundred consecutive patients who received clopidogrel and were scheduled to undergo primary CABG. In 64 of these patients, CABG was delayed at least 5 days after clopidogrel treatment (group A). The other 36 patients received clopidogrel treatment within 5 days of undergoing CABG (group B).

MEASUREMENTS AND MAIN RESULTS

Data were collected on patient demographics, time of last clopidogrel dose, preoperative anticoagulant and/or antiplatelet agents administered, surgical characteristics, intraoperative transfusions, blood products transfused, and chest tube output for 24 hours after surgery. No significant differences in baseline characteristics or intraoperative variables (number of bypasses, aortic cross-clamp time, and cardiopulmonary bypass time) were noted between the two groups. Mean +/- SD number of packed red blood cell units/patient was 1.1 +/- 1.4 in group A versus 2.1 +/- 2.5 in group B (p=0.009). Mean +/- SD number of platelet units/patient transfused was 0.5 +/- 0.9 in group A versus 1.9 +/- 1.6 in group B (p<0.001). When comparing a subset of 21 patients who received clopidogrel within 72 hours of surgery with the 64 whose CABG was delayed at least 5 days after clopidogrel treatment, the transfusion rates were significantly higher (95% vs 52%, p<0.05). Specifically, the mean +/- SD number of transfused units/patient of red blood cells (3.1 +/- 2.8 vs 1.1 +/- 1.4, p<0.005) and platelets (2.6 +/- 1.5 vs 0.5 +/- 0.9, p<0.007) was greater in patients who received clopidogrel within 72 hours of surgery.

CONCLUSION

A strategy to delay CABG after clopidogrel treatment led to reduced blood product administration. The optimal waiting period after clopidogrel treatment is not known but appears to be at least 5 days before CABG.

Effects of Preoperative Abciximab and Eptifibatide on Bleeding Indices in Coronary Artery Bypass Graft Patients

Background:

Glycoprotein (GP) IIb/IIIa antagonists are used routinely for the treatment of acute coronary syndrome and to prevent thromboses during percutaneous coronary interventions. It is not uncommon for patients who initially require a GP IIb/IIIa inhibitor to eventually receive a surgical intervention.

Objective:

To compare the difference in bleeding indices in patients who undergo coronary artery bypass grafting (CABG) after receiving either eptifibatide or abciximab.

Methods:

A retrospective chart review was completed on all adults who received abciximab or eptifibatide within 24 hours prior to undergoing CABG. Patients were excluded if they had received a dose of warfarin within 96 hours prior to the procedure or if they had an incomplete medical record, an off-pump procedure, a known hypercoagulable disorder, or hemophilia. A total of 54 patients were included and preoperative data, including doses of anticoagulant and antiplatelet agents, were recorded. Intraoperative and postoperative data collected for analysis included hemoglobin level, chest tube output, and the amount of blood products transfused for 24 hours postprocedure.

Results:

There was a statistically significant difference between the eptifibatide and abciximab groups in the amount of fresh frozen plasma (mean ± SD, 21 ± 31 vs 187 ± 125 mL, respectively; p < 0.05) and platelets (212 ± 81 vs 433 ± 118 mL, respectively; p < 0.01) transfused during the intraoperative period. However, when the total amount of blood products transfused intraoperatively (769 ± 243 vs 1395 ± 316 mL, respectively; p = 0.47) was evaluated, no significant difference was detected. Likewise, markers for bleeding that were collected during the 24-hour postoperative window (immediate and 24-h postoperative hemoglobin and total 24-h chest tube output) were not significantly different.

Conclusions:

Although there is an increased risk of bleeding when abciximab or eptifibatide is administered prior to CABG, no significant difference in the total amount of blood products used was detected between the 2 agents in this study.

Coronary artery bypass grafting with single cross-clamp results in fewer persistent neuropsychological deficits than multiple clamp or off-pump coronary artery bypass grafting

BACKGROUND

In coronary artery bypass grafting (CABG) patients, neuropsychological deficits that are present from the time of the operation through 6 months postoperatively are considered permanent and represent organic brain damage related to the operation. We hypothesized that changes in our surgical method would reduce persistent deficits.

METHODS

From 1999 to 2004, consenting CABG patients were randomly assigned to multiple aortic cross-clamp or single aortic cross-clamp technique. An additional contemporary group of patients treated with off-pump CABG was studied. All patients underwent an 11-part neuropsychologic examination preoperatively, and at 1 week, 6 weeks, and 6 months postoperatively. One hundred seven patients with no postoperative neurologic deficits had neuropsychologic examinations at all four testing periods.

RESULTS

Off-pump CABG patients were significantly younger (60 +/- 11 years) than multiple aortic cross-clamp (66 +/- 8 years) and single aortic cross-clamp (64 +/- 9 years; p < 0.05) patients. At 6 months, 26% of 27 multiple aortic cross-clamp patients had neuropsychological deficits, 27% of 26 off-pump CABG patients had neuropsychological deficits, and only 9% of 54 single aortic cross-clamp patients had neuropsychological deficits (p = 0.067 versus multiple aortic cross-clamp and off-pump CABG).

CONCLUSIONS

These results suggest that surgical technique is very important in determining cognitive outcome after CABG. Cardiopulmonary bypass is not the most important factor in determining outcome and when carefully performed with single cross-clamp and minimal aortic manipulation is equal or may be superior to off-pump operation. We suspect that mild hypothermia in on-pump surgery is additionally neuroprotective, a factor that should be taken into account when planning an operation.

Coronary Insufficiency After Stentless Aortic Root Replacement: Risk Factors and Solutions

BACKGROUND

Coronary insufficiency is a dreaded complication of total aortic root replacement (ARR) with few defined risk factors. This study describes the incidence, risk factors, management options, and outcomes of this condition after ARR with stentless porcine valves.

METHODS

The study consisted of a retrospective analysis of 503 patients (mean age, 68.9 +/- 10.2 years) undergoing stentless porcine total ARR (Medtronic Freestyle and St. Jude Toronto) between the years 1993 and 2005 at a single institution. Coronary insufficiency was defined as the need for unplanned bypass grafting during, or after removal from cardiopulmonary bypass to correct wall motion abnormalities, arrhythmias, or right ventricular failure in the absence of known obstructive coronary disease.

RESULTS

A total of 13 cases of right coronary artery and no cases of left coronary insufficiency were identified (overall incidence 13 of 503, 2.6%). All were treated with aortocoronary bypass grafting to the right coronary artery using saphenous vein. Compared with patients who did not have coronary insufficiency, patients with this complication were more likely to be female (11 of 13, 85%, versus 201 of 490, 41%; p = 0.006), had higher mean body mass index (34.6 +/- 12.0 kg/m2 versus 28.3 +/- 3.8 kg/m2, p = 0.04), and were implanted with smaller prostheses (23.9 +/- 2.1 mm versus 25.6 +/- 2.4 mm, p = 0.026), a finding not explained by the preponderance of female sex. Mean age, ejection fraction, and other demographic variables were similar. Despite longer cardiopulmonary bypass times (238 +/- 61 minutes versus 180 +/- 35 minutes, p = 0.005), operative mortality was not significantly different (1 of 13, 7.7%, versus 29 of 490, 5.9%; p = not significant).

CONCLUSIONS

Coronary artery insufficiency is uncommon after stentless aortic root replacement and more often affects the right coronary artery. Risk factors appear to be female sex, higher body mass index, and small aortic root. Preventive measures include recognition of coronary orientation, routine valve rotation, and adequate coronary button mobilization. When this complication occurs, good outcomes can still be obtained with early recognition and prompt bypass grafting.

Single crossclamp improves 6-month cognitive outcome in high-risk coronary bypass patients: The effect of reduced aortic manipulation

OBJECTIVE

We hypothesized that a strategy that reduced aortic manipulation would reduce the incidence of cognitive deficits in patients undergoing coronary artery bypass grafting compared with the "traditional" approach and that neurobehavioral outcomes with the reduced aortic manipulation strategy would approach those obtained with off-pump coronary artery bypass surgery.

METHODS

Consenting high-risk patients (those with older age, diabetes, or hypertension) scheduled for coronary artery bypass grafting and cardiopulmonary bypass were randomly assigned to 1 of 2 aortic management protocols: (1) a traditional approach in which distal anastomoses were accomplished while the aorta was crossclamped but in which proximal anastomoses were sewn while a partial occlusion clamp was applied to the aorta (multiple aortic clamping group) or (2) a reduced aortic manipulation approach in which the aorta was clamped a single time with a reduced-pressure clamp (single aortic clamping group) and the partial occlusion clamp was not used. A contemporaneous group of patients undergoing off-pump coronary artery bypass surgery without cardiopulmonary bypass was also enrolled. Subjects in all 3 groups underwent neurologic and neuropsychological testing before and after surgery. After randomization, patients assigned to either approach could be changed to another strategy if the attending surgeon determined that patient safety demanded this change. The study design anticipated that surgical techniques would evolve over the course of patient enrollment and anticipated that some patients would have intraoperative echocardiographic findings that would demand that the traditional approach (eg, severe aortic atherosclerosis) or the reduced manipulation protocol (eg, severe ischemia or poor left ventricular function) be abandoned. Thus, an unequal distribution of patients was expected. By surgeon decision, 20 of 84 multiple aortic clamping patients crossed over to single aortic clamping, and 3 of 85 single aortic clamping patients switched to multiple aortic clamping. Eligible patients had a battery of neuropsychological tests before surgery and at 6 months after surgery. A 20% decrement in 2 or more tests was defined as a neuropsychological deficit.

RESULTS

[table: see text].

CONCLUSIONS

A surgical strategy designed to minimize aortic manipulation can significantly reduce the incidence of cognitive deficits in coronary artery bypass grafting patients compared with traditional techniques. In this series, the results of the reduced aortic manipulation strategy were not significantly different from those in patients having off-pump coronary artery bypass surgery, thus emphasizing surgical technique as the primary cause of brain damage in coronary artery bypass grafting patients.

Does the Combination of Aprotinin and Angiotensin-Converting Enzyme Inhibitor Cause Renal Failure After Cardiac Surgery?

BACKGROUND

Aprotinin use in cardiac surgery has been associated with mild elevations in serum creatinine but generally has not been associated with an increase in the risk of acute renal failure. In the presence of angiotensin-converting enzyme (ACE) inhibitors, however, aprotinin may contribute to significant reductions in glomerular perfusion pressure. The purpose of this study was to test the hypothesis that the combination of ACE inhibitors and aprotinin cause renal failure after cardiac surgery.

METHODS

The study consisted of a retrospective investigation of all adult patients undergoing coronary artery bypass graft, valve, or combined procedures during the years 2000 to 2002 at a single institution. Aprotinin was administered selectively for reoperations, combined procedures, and other operations deemed to be at higher risk for bleeding. Excluded from analysis were patients with preoperative serum creatinine greater than 1.5 mg/dL, a history of renal failure, emergent or salvage procedures, preoperative use of intraaortic balloon pump, and off-pump procedures. Perioperative renal failure was defined as creatinine greater than 2.0 mg/dL within 72 hours of surgery. Preoperative demographic and intraoperative variables were analyzed with univariate and logistic regression analysis with odds ratio (OR) and bootstrap validation.

RESULTS

A total of 1,209 patients were included. The incidence of perioperative renal failure was 3.5%, and mortality in this group was 48%. Controlling for other demographic and intraoperative variables that may affect renal function (age, sex, diabetes mellitus, hypertension, New York Heart Association class, prior cardiac surgery, valve procedures, cardiopulmonary bypass time, aortic cross-clamp time, lowest hematocrit during cardiopulmonary bypass, transfusions) the preoperative use of ACE inhibitors along with intraoperative use of aprotinin was significantly associated with acute renal failure (OR 2.9, 95% confidence interval [CI]: 1.4 to 5.8, p < 0.0001). The effect of either drug alone was not significant. Other identified risk factors included age (OR 1.2 per year, CI: 1.01 to 1.5, p = 0.035), valve procedure (OR 2.7, CI: 1.3 to 5.7, p = 0.016), lowest hematocrit on cardiopulmonary bypass (OR 2.2, CI: 1.6 to 3.2, p < 0.0001), and transfusions of red blood cells (OR 1.04 per unit, CI: 1.02 to 1.06, p < 0.0001) and platelets (OR 1.7 per unit, CI: 1.2 to 2.4, p = 0.001).

CONCLUSIONS

The combination of preoperative use of ACE inhibitors and intraoperative use of aprotinin should be avoided in cardiac surgery.

Metastatic thymic carcinoid: a case report

Thymic neuroendocrine carcinomas (carcinoid) are rare tumors. They have malignant potential, the capacity for distant metastasis, and often present with associated endocrinopathies. This report describes a patient who was diagnosed with thymic carcinoid and Cushing syndrome at age 19 that, despite complete surgical excision of his tumor, developed local recurrence with distant metastases to his brain, lungs, and bone. We discuss the evolution of this patient's illness as well as the therapies used in his care. Due to the nature of these tumors to recur both locally and distant, the importance of aggressive surgical management is emphasized. We also discuss the role of adjuvant therapy, which in our case consisted of chemotherapy, radiotherapy, and several new therapies including an antiangiogenesis agent and a tyrosine kinase inhibitor.

Anterior leaflet augmentation for ischemic mitral regurgitation

BACKGROUND

Mitral valve repair improves survival and quality of life in patients with ischemic mitral regurgitation (MR). Although many repair methods exist for this condition, the ideal approach remains unknown. The purpose of this study is to describe a simple technique for repair of ischemic MR that addresses the pathophysiology of tethered leaflets and to report its early results.

METHODS

The technique consists of pericardial patch enlargement of the anterior mitral leaflet and placement of a flexible annuloplasty band. Candidates for the repair had ischemic cardiomyopathy and echocardiographic evidence of moderate or severe Carpentier type IIIb MR. Patients were followed with serial echocardiography.

RESULTS

Between January 2002 and November 2003, 25 adult patients underwent anterior leaflet augmentation for ischemic MR. Mean age was 64.8 +/- 10.6 years, and mean left ventricular ejection fraction was 0.36 +/- 0.14. Preoperative MR by transesophageal echocardiography was severe in 84% of patients and moderate in 16%. Annuloplasty band sizes were 27 mm to 31 mm (mean, 28.4 +/- 1.1 mm). Concomitant coronary artery bypass grafting was performed in all patients. Transesophageal echocardiography immediately after repair revealed MR to be none or trace in 80% of patients and mild in 20%. No intraoperative conversion to valve replacement was performed. In follow-up, 2 patients have experienced moderate MR and are being treated medically, and no patients have mitral stenosis. At 2 years, actuarial freedom from moderate or greater MR is 81%.

CONCLUSIONS

For patients with ischemic MR, anterior leaflet augmentation is a simple and reproducible method of valve repair that addresses the pathophysiology of tethered leaflets. Early results in a small number of patients have been encouraging.

Selective management of cardiovascular dysfunction in posttraumatic SIRS and sepsis

Cardiovascular dysfunction associated with the systemic inflammatory response syndrome (SIRS) is caused by a combination of decreased myocardial contractility and low vascular resistance. The contribution of each of these components can be determined at the bedside, and directed therapy can be appropriately initiated. Over an 8-month period of time, 23 consecutive patients who experienced posttraumatic SIRS while still being monitored with a volumetric pulmonary artery catheter (PAC) were prospectively evaluated. Ventricular pressure-volume diagrams were constructed to quantify myocardial contractility and afterload. In a resuscitation protocol, dobutamine was administered to patients with an isolated decrease in contractility, and dopamine or epinephrine was instituted for the combination of reduced contractility and afterload. Variables describing cardiovascular function were measured at the time of resolution of initial shock resuscitation (BASE), at the onset of SIRS (ONSET), and after administration of inotropic or vasoactive agents (TREAT). ONSET was associated with a significant decrease in left ventricular power (LVP) (362 +/- 96 to 235 +/- 55 mmHg.L/min/m(2), P < 0.00001) and stroke work index (SWI) (4670 +/- 1213 to 3060 +/- 848 mmHg.mL/m, P < 0.00001) from BASE. Sixteen patients (70%) demonstrated predominantly decreased contractility, which returned to near BASE values after the administration of dobutamine. The remaining seven patients (30%) had both decreased contractility and afterload, which was treated with dopamine or epinephrine. LVP and SWI significantly increased (235 +/- 55 to 328 +/- 77 mmHg.L/min/m(2), P < 0.00001, and 3060 +/- 848 to 4554 +/- 1423 mmHg.mL/m(2), P < 0.00001, respectively) on the initiation of directed therapy. Specific cardiovascular abnormalities can be identified at the bedside, and this information can guide pharmacologic management. Directed therapy improves cardiovascular function.

Dissection in a pulmonary autograft

We report the case of a type II aortic dissection involving the pulmonary autograft after a Ross procedure 6 years earlier. A dissection flap was present in both the native ascending aorta and right coronary sinus of the autograft. At reoperation, the valve was spared using a root remodeling technique.

Diagnosis of an Intraoperative Aortic Dissection by Transesophageal Echocardiography During Routine Coronary Artery Bypass Grafting Surgery

Acute aortic dissection during coronary artery bypass grafting (CABG), though rare, causes significant morbidity and mortality. We report a case of postcardiopulmonary bypass aortic dissection in a 73-yr-old man who presented for CABG. The diagnosis was made by transesophageal echocardiography and allowed immediate treatment of the potentially lethal complication.

IMPLICATIONS

Acute aortic dissection during coronary artery bypass grafting (CABG), though rare causes frequent morbidity and mortality. We report a case of postcardiopulmonary bypass aortic dissection in a 73-yr-old man who presented for CABG. Diagnosis made by transesophageal echocardiography allowed immediate treatment of the potentially lethal complication.

Effects of preoperative enoxaparin versus unfractionated heparin on bleeding indices in patients undergoing coronary artery bypass grafting

BACKGROUND

We examined the effects of preoperative administration of enoxaparin (ENOX), a low-molecular-weight heparin, on bleeding indices and transfusion rates in patients undergoing coronary artery bypass grafting (CABG).

METHODS

Patients undergoing isolated CABG between 1997 and 2002 who received preoperative ENOX or a continuous infusion of unfractionated heparin (UFH) were randomly divided into three groups: continuous UFH, ENOX last administered more than 12 hours before surgery (ENOX > 12), and ENOX administered less than 12 hours before surgery (ENOX < 12). Perioperative hemoglobin values, transfusion rates, and bleeding complications were compared.

RESULTS

A total of 69, 58, and 34 patients comprised the UFH, ENOX > 12, and ENOX < 12 groups, respectively. Preoperative demographics and hematologic data were similar among the groups. Compared with the UFH group, the ENOX < 12 group had significantly lower postoperative hemoglobin values (9.6 +/- 1.3 g/dL versus 10.4 +/- 1.2 g/dL, p < 0.05), higher transfusion rates (73.5% versus 50.7%, p < 0.05), and required more total packed red cells per patient (882 +/- 809 mL versus 472 +/- 626 mL, p < 0.05). A nonsignificant increase was noted in the risk of returning to the operating room for bleeding in patients who had received ENOX compared with patients receiving UFH (6.5% versus 2.9%).

CONCLUSIONS

The preoperative use of ENOX less than 12 hours before CABG is associated with lower postoperative hemoglobin values and higher rates of transfusion than continuous UFH.

Excessive argatroban anticoagulation for heparin-induced thrombocytopenia

OBJECTIVE

To report 4 patients who became excessively anticoagulated with the recommended or lower starting doses of argatroban during treatment for heparin-induced thrombocytopenia type II (HIT-II) in a cardiothoracic intensive care unit.

CASE SUMMARY

Four patients were treated with argatroban after confirmation of HIT-II after cardiac surgery. In 3 patients, argatroban was initiated at the recommended starting dose of 2 micro g/kg/min; in 1 patient, therapy was initiated at 1 micro g/kg/min. All patients had relatively normal hepatic function. In all cases, the resulting activated partial thromboplastin time was supertherapeutic and exceeded 100 seconds in 3 patients. Additionally, argatroban clearance appeared to be prolonged upon discontinuation.

DISCUSSION

Argatroban pharmacokinetics in critically ill patients have not been investigated. Our case series demonstrates the potential over-anticoagulation that can occur in this patient population despite relatively normal hepatic function. An objective causality assessment revealed that the adverse drug event in these patients was probably caused by administration of argatroban.

CONCLUSIONS

Formal pharmacokinetic studies of argatroban are needed in critically ill patients in order to optimize therapy.

Admission base deficit in pediatric trauma: a study using the National Trauma Data Bank

BACKGROUND

The base deficit, an important indicator of physiologic derangement after severe injury in adults, has not been specifically examined in the pediatric trauma population. The purpose of this study was to assess the ability of the admission base deficit to predict injury severity and outcome in the pediatric trauma population.

METHODS

The study group included all patients in the National Trauma Data Bank over a 2-year period aged 0 to 12 years with a base deficit (0 to -30 mEq/L) recorded from the emergency department. Age, presence of a severe closed head injury, and base deficit were analyzed with respect to mortality and other indicators of injury severity.

RESULTS

A total of 515 patients constituted the study group. Base deficit less than -4 mEq/L (p < 0.001) and the presence of a closed head injury (odds ratio, 3.8; p < 0.05) were predictors of mortality. For the group, an admission base deficit of -8 mEq/L corresponded to a probability of mortality of 25%. Significant correlations were found between base deficit and emergency department systolic blood pressure, Injury Severity Score, and Revised Trauma Score. There was no relationship between age and mortality.

CONCLUSION

In injured children, the admission base deficit reflects injury severity and predicts mortality. The probability of mortality increases precipitously in children with a base deficit less than -8 mEq/L, and should alert the clinician to the presence of potentially lethal injuries or uncompensated shock.

Determining optimal cardiac preload during resuscitation using measurements of ventricular compliance

BACKGROUND

While the right ventricular end-diastolic volume index (RVEDVI) has been shown to be a better indicator of preload than cardiac filling pressures, optimal values during resuscitation from trauma are unknown. This study examines right ventricular stiffness as a guide to optimal values of RVEDVI.

METHODS

Prospective study of 19 critically injured patients monitored with a volumetric pulmonary artery catheter during resuscitation. Per resuscitation protocol, the target RVEDVI was > or = 120 mL/m2. Sequential fluid boluses of 500 to 1000 mL were administered to obtain at least four values of RVEDVI and right ventricular end-diastolic pressure (estimated by central venous pressure [CVP]). For each patient, nonlinear regression was used to construct the ventricular compliance curve based on the equation, CVP = aek(RVEDVI), where k is the coefficient of chamber stiffness.

RESULTS

Overall, the derived compliance curves had excellent fit with the theoretical equation (mean R2, 0.95 +/- 0.04). Mean k was 0.043 +/- 0.012 (range, 0.029-0.067). For each patient, mean RVEDVI during resuscitation was significantly correlated with k (R2 = 0.75, p < 10-5) indicating that chamber stiffness, measured during initial fluid administration, may be used to determine RVEDVI during the ensuing resuscitation.

CONCLUSION

In critically injured patients, bedside assessment of right ventricular compliance is possible and may help determine optimal values of RVEDVI during resuscitation.

Processing scavenged blood with a cell saver reduces cerebral lipid microembolization

BACKGROUND

Microembolization during cardiopulmonary bypass (CPB) can be detected in the brain as lipid deposits that create small capillary and arteriolar dilations (SCADs) with ischemic injury and neuronal dysfunction. SCAD density is increased with the use of cardiotomy suction to scavenge shed blood. Our purpose was to determine whether various methods of processing shed blood during CPB decrease cerebral lipid microembolic burden.

METHODS

After hypothermic CPB (70 minutes), brain tissue from two groups of mongrel dogs (28 to 35 kg) was examined for the presence of SCADs. In the arterial filter (AF) group (n = 12), shed blood was collected in a cardiotomy suction reservoir and reinfused through the arterial circuit. Three different arterial line filters (Pall LeukoGuard, Pall StatPrime, Bentley Duraflo) were used alone and in various combinations. In the cell saver (CS) group (n = 12), shed blood was collected in a cell saver with intermittent preocessing (Medtronic autoLog model) or a continuous-action cell saver (Fresenius Continuous Auto Transfusion System) and reinfused with and without leukocyte filtration through the CPB circuit.

RESULTS

Mean SCAD density (SCAD/cm2) in the CS group was less than the AF group (11 +/- 3 vs 24 +/- 5, p = 0.02). There were no significant differences in SCAD density with leukocyte filtration or with the various arterial line filters. Mean SCAD density for the continuous-action cell saver was 8 +/- 2 versus 13 +/- 5 for the intermittent-action device.

CONCLUSIONS

Use of a cell saver to scavenge shed blood during CPB decreases cerebral lipid microembolization.

Maintaining survivors' values of left ventricular power output during shock resuscitation: a prospective pilot study

OBJECTIVE

Maintaining left ventricular power output (LVP) > 320 mm Hg x L/min/m2 during resuscitation has been retrospectively associated with faster resolution of acidosis and survival after posttraumatic shock. The purpose of this prospective study was to evaluate the effects of maintaining LVP above this threshold during resuscitation on base deficit clearance, organ failure, and survival.

METHODS

This was a study of a consecutive series of critically injured patients (PWR) monitored with a pulmonary artery catheter during initial resuscitation. LVP, calculated as cardiac index-(mean arterial pressure-central venous pressure), was maintained >320 mm Hg x L/min/m2 via a predefined protocol by using ventricular pressure-volume diagrams. Outcome was assessed by base deficit clearance (<6 mEq/L) in <24 hours, lowest base deficit in the first 24 hours after admission (24-hr base deficit), organ dysfunctions/patient, and survival. Results were compared with 39 control patients (OXY) with identical enrollment criteria from a previous prospective study who were resuscitated based on oxygen transport criteria.

RESULTS

Twenty patients were studied over a 6-month period. Mean LVP during resuscitation in the PWR group was 360 +/- 100 mm Hg x L/min/m2. Admission base deficit was similar between the two groups (PWR 11 +/- 4.2 vs. OXY 11 +/- 5.8 mEq/L;p = 0.66). More PWR patients cleared base deficit in < 24 hours than OXY patients (16 of 20 vs. 17 of 39, p = 0.009, Fisher's exact test), and the PWR patients had a significantly lower 24-hr base deficit (3.9 +/- 3.7 vs. 7.1 +/- 4.6 mEq/L, p = 0.01). Organ dysfunction rate was lower in the PWR group (2.1 +/- 1.5 vs. 3.2 +/- 1.4 organ dysfunctions/patient, p = 0.007). Survival in the PWR group was 15 of 20, versus 21 of 39 in the OXY group (p = 0.10).

CONCLUSION

Prospectively maintaining LVP above 320 mm Hg x L/min/m2 during resuscitation is an achievable goal. It is associated with improved base deficit clearance and a lower rate of organ dysfunction after resuscitation from traumatic shock.

“Blind” Placement of Long-Term Central Venous Access Devices: Report of 589 Consecutive Procedures

Placement of long-term central venous access devices, such as Hickman catheters and implanted subcutaneous ports, has traditionally been performed in the operating room with fluoroscopy. This study reports our experience with percutaneous placement of these devices in the outpatient clinic setting without the use of real-time imaging. Results were generated from a prospective database of all adult patients undergoing placement of central venous access in the outpatient clinic of the Wake Forest University Baptist Medical Center. This database revealed that during the years 1996 and 1997, long-term central venous catheter placement was attempted in 589 adult patients in the outpatient clinic. Technical success was achieved in 558 patients (92%). This included 278 tunneled catheters and 280 totally implanted devices. Repositioning of the catheter tip was required in 16 patients (2.9%). The incidence of pneumothorax was 1.9 per cent. Late complications, including infection and thrombosis, occurred in 9 per cent. The average procedure-related charge for placement of a single-lumen central venous port in the outpatient clinic was $1691 versus $4559 in the operating room and $3890 in the radiology department. We conclude that routine placement of long-term central venous access devices in the outpatient clinic, without the use of real-time imaging, yields acceptable success rates and may have economic advantages over procedures performed in the operating room or radiology department.

"Blind" placement of long-term central venous access devices: report of 589 consecutive procedures

Placement of long-term central venous access devices, such as Hickman catheters and implanted subcutaneous ports, has traditionally been performed in the operating room with fluoroscopy. This study reports our experience with percutaneous placement of these devices in the outpatient clinic setting without the use of real-time imaging. Results were generated from a prospective database of all adult patients undergoing placement of central venous access in the outpatient clinic of the Wake Forest University Baptist Medical Center. This database revealed that during the years 1996 and 1997, long-term central venous catheter placement was attempted in 589 adult patients in the outpatient clinic. Technical success was achieved in 558 patients (92%). This included 278 tunneled catheters and 280 totally implanted devices. Repositioning of the catheter tip was required in 16 patients (2.9%). The incidence of pneumothorax was 1.9 per cent. Late complications, including infection and thrombosis, occurred in 9 per cent. The average procedure-related charge for placement of a single-lumen central venous port in the outpatient clinic was $1691 versus $4559 in the operating room and $3890 in the radiology department. We conclude that routine placement of long-term central venous access devices in the outpatient clinic, without the use of real-time imaging, yields acceptable success rates and may have economic advantages over procedures performed in the operating room or radiology department.

Threshold values of intramucosal pH and mucosal-arterial CO2 gap during shock resuscitation

BACKGROUND

The gastric intramucosal pH (pHi) and gastric mucosal-arterial CO2 gap (GAP) estimate visceral perfusion and predict outcome. Threshold values of these variables for use during resuscitation, however, remain poorly defined. The purpose of this study was to develop clinically derived cutoffs for both pHi and GAP for predicting death and multiple organ failure (MOF) in trauma patients.

METHODS

This was a cohort study of 114 consecutive trauma patients who had pHi determined at 24 hours after intensive care unit admission. The corresponding GAP for each of these values of pHi was obtained through chart review. Receiver operating characteristic curves were constructed for both pHi and GAP with respect to death and MOF. These curves were used to determine the value of each variable that maximized the sum of sensitivity and specificity in predicting outcome. chi2 tests and odds ratios were used to determine if significant differences in outcome occurred above and below these cutoff values.

RESULTS

Of 114 patients who had pHi determined at 24 hours after admission, 108 had corresponding GAP values available. The values of pHi and GAP that maximized sensitivity and specificity were 7.25 and 18 mm Hg, respectively. The odds ratio for pHi versus death was 4.6 and for pHi versus MOF was 4.3. The odds ratios for GAP versus death and MOF were 2.9 and 3.3, respectively.

CONCLUSION

In trauma patients, the ability to predict death and MOF is maximized at values of pHi less than 7.25 and GAP greater than 18 mm Hg. These values represent clinically derived cutoffs that should be useful for evaluating the adequacy of intestinal perfusion during resuscitation.

Elevated arterial base deficit in trauma patients: a marker of impaired oxygen utilization

BACKGROUND

In trauma patients, the admission value of arterial base deficit stratifies injury severity, predicts complications, and is correlated with arterial lactate concentration. In theory, elevated base deficit and lactate concentrations after shock are related to oxygen transport imbalance at the cellular level. The purpose of this study was to test the hypothesis that an elevated base deficit in trauma patients is indicative of impaired systemic oxygen utilization and portends poor outcomes.

METHODS

This study was a retrospective analysis of a prospectively collected database. The study population included all patients admitted to the trauma intensive care unit at a Level 1 trauma center during a 12-month period who were monitored with a pulmonary artery catheter and serial measurements of lactate and base deficit, and who achieved a normal arterial lactate concentration (< 2.2 mmol/L) with resuscitation. The patients were divided into those who maintained a persistently high base deficit (> or = 4 mmol/L) and those who achieved a low base deficit (< 4 mmol/L) during resuscitation.

RESULTS

One-hundred patients (mortality 20%) were monitored with a pulmonary artery catheter and achieved a normal arterial lactate concentration. The mean age+/-SD (SEM) of the group was 37+/-17 years and the Injury Severity Score was 25+/-11. Subgroup analysis revealed that patients with a persistently high base deficit (n=26) had higher rates of multiple organ failure (35% versus 5%, p < 0.001) and death (50% versus 9%, p < 0.00001) compared with patients who achieved a low base deficit. Patients with a persistently high base deficit also had lower oxygen consumption (126+/-40 mL/m2 versus 156+/-30 mL/m2, p=0.01 at 48 hours) and a lower oxygen utilization coefficient (0.20+/-0.05 versus 0.24+/-0.03, p=0.01 at 48 hours) compared with patients with a low base deficit. At 48 hours, both oxygen consumption (r=-0.44, [r, correlation coefficient] p=0.002) and oxygen utilization (r=-0.46, p=0.001) had a significant negative correlation with base deficit.

CONCLUSIONS

In trauma patients, a persistently high arterial base deficit is associated with altered oxygen utilization and an increased risk of multiple organ failure and mortality. Serial monitoring of base deficit may be useful in assessing the adequacy of oxygen transport and resuscitation.

Enalaprilat improves gut perfusion in critically injured patients

Inadequate splanchnic perfusion, detected as a low gastric intramucosal pH (pHi), in the face of normal systemic perfusion predicts an increased risk for multiple organ failure after trauma. Although the exact etiology of this low pHi is unknown, angiotensin II is thought to be an important regulator of gut perfusion during and after resuscitation from shock. The purpose of this study is to determine whether enalaprilat, an angiotensin-converting enzyme inhibitor, improves gut perfusion in critically injured patients. To test this hypothesis, 18 trauma patients monitored with a nasogastric tonometer and a pulmonary artery catheter were enrolled in a prospective study. A single dose of enalaprilat, .625 mg, was given as an i.v. bolus or a 4 h infusion following systemic resuscitation. Pre- and postdrug tonometric and hemodynamic data, including cardiac index, mean arterial pressure, right ventricular end-diastolic volume index, systemic vascular resistance index, and oxygen transport variables were compared using the paired t test. Results demonstrate that pHi was significantly improved after 4 h (7.13 +/- .04 to 7.19 +/- .03, p = .03) and after 24 h compared with baseline (7.14 +/- .04 to 7.25 +/- .04, p = .04). Overall, pHi increased in 12 of 18 patients. No significant differences were observed in any of the studied hemodynamic or systemic perfusion variables including mean arterial pressure (92 +/- 4 to 87 +/- 4, p = .24) and oxygen delivery (669 +/- 33 to 675 +/- 32, p = .82). In examining the determinants of pHi, the intramucosal-arterial PCO2 difference was improved after enalaprilat administration (27 +/- 6 to 17 +/- 3 mmHg, p = .04) while no difference was observed in arterial bicarbonate (19.5 +/- .7 to 19.7 +/- .8, p = .90). Additionally, the change in pHi observed with enalaprilat correlated with predrug intramucosal-arterial PCO2 difference (r = .74, r2 = .55, p = .0005). These results demonstrate that enalaprilat improves gut perfusion as measured by gastric tonometry in critically injured patients, and that this effect appears to be independent of changes in systemic perfusion.