Infected biatrial myxoma: transesophageal echocardiography-guided surgical resection

We identified a biatrial myxoma using transesophageal echocardiography whose right atrial component was missed with conventional transthoracic techniques. Identifying the biatrial component directs a safer approach to right heart catheterization. Infected biatrial myxomas are both rare and successfully managed using prolonged intravenous antibiotic therapy followed by resection. Atrial septal defects created during the resection of an infected myxoma may be safely repaired using a prosthetic patch.

Influence of hydrogen ion concentration versus carbon dioxide tension on pulmonary vascular resistance after cardiac operation

Disturbances of respiratory acid-base status are common in patients supported with mechanical ventilation of the lungs after cardiac operations. This study was conducted with two protocols. The purpose was to determine whether respiratory acid-base status influences pulmonary vascular resistance in adults after cardiac operations and whether the influence is mediated by hydrogen ion concentration or carbon dioxide tension. Patients were studied while under general anesthesia immediately after aorta-coronary bypass. In the first protocol, with seven patients, arterial carbon dioxide tension was manipulated by the addition of 5% carbon dioxide to the breathing circuit. Pulmonary vascular resistance index was determined as arterial carbon dioxide tension rose from 30 mm Hg to 50 mm Hg and back to 30 mm Hg. In the second protocol, with 10 different patients, hydrogen ion concentration was manipulated by the addition of 0.2N hydrochloric acid, sodium bicarbonate, or both as arterial carbon dioxide tension was held constant. We used analysis of variance for statistical data. The results of the first protocol showed that pulmonary vascular resistance index rose by 44% (p < 0.05) as arterial carbon dioxide tension rose from 30 to 50 mm Hg. The results of the second protocol showed that changes in pulmonary vascular resistance index were parallel to changes in hydrogen ion concentration as arterial carbon dioxide tension was held constant (p < 0.05). These data demonstrate that respiratory acid-base status is an important determinant of pulmonary vascular resistance in the adult after cardiac operations. Furthermore, these data suggest the effect is mediated by hydrogen ion concentration, not carbon dioxide tension.

Peripheral bypass-induced pulmonary and coronary vascular injury. Association with increased levels of tumor necrosis factor

BACKGROUND

Although cardiopulmonary bypass is associated with systemic complement activation and neutrophil sequestration, it is unclear whether bypass-induced vascular injury is localized and dependent on organ ischemia. We hypothesized that other factors perhaps related to placement of a bypass circuit or to blood perfusion of a pump-oxygenator system may produce vascular injury caused by systemically circulating mediators. In dogs, we determined whether application of a systemic venoarterial bypass circuit with pump-oxygenator perfusion but without pulmonary or cardiac flow diversion (peripheral bypass) leads to vascular injury. Since several features of the postperfusion syndrome after bypass resemble sequelae of endotoxin exposure, we also measured circulating endotoxin and tumor necrosis factor levels.

METHODS AND RESULTS

Anesthetized dogs underwent 2 hours of exposure to a pump-oxygenator with peripheral venoarterial bypass. We used a double indicator measurement of pulmonary and coronary vascular permeability (protein leak index [PLI]) as indexes of vascular injury. Compared with controls (n = 7), the pulmonary PLI of dogs undergoing bypass (n = 11) increased more than threefold (18.8 +/- 2.3 vs 63.3 +/- 7.6 x 10(-4) min-1; P < .05) and the coronary PLI increased more than twofold (P < .05). The rate of disappearance of intravascular radiolabeled protein increased threefold after bypass (disappearance t1/2, 241 +/- 35 vs 84 +/- 15 minutes, control vs bypass; P < .05), suggesting a generalized increase in vascular permeability. Circulating endotoxin was detectable in blood samples from 8 of 8 bypass animals (range, 0.24 to 4.56 ng/mL) compared with 2 of 5 controls (P < .05). Tumor necrosis factor levels increased significantly with bypass (6.7 +/- 3.8 vs 146.7 +/- 33.6 U/mL, baseline vs bypass; P < .05) and were only slightly and nonsignificantly increased in controls (7.0 +/- 4.4 vs 18.2 +/- 5.9 U/mL; P = NS). Peak tumor necrosis factor but not peak endotoxin levels correlated with pulmonary and with coronary protein leak. As expected, circulating complement (CH50) levels decreased significantly during bypass, reflecting systemic complement activation. However, the levels correlated poorly with the severity of vascular injury.

CONCLUSIONS

We conclude that peripheral pump-oxygenator bypass causes coronary and pulmonary vascular injury that is independent of blood flow diversion and is associated with the appearance of circulating levels of endotoxin and tumor necrosis factor, which may play a role in bypass-induced vascular injury.

5-Fluorouracil, hydroxyurea and escalating doses of iododeoxyuridine with concomitant radiotherapy for malignant gliomas: a clinical and pharmacologic analysis

BACKGROUND

Iododeoxyuridine (IUdR) is a known radiation enhancer, and interacts biochemically with 5-fluorouracil (5-FU) and hydroxyurea (HU).

PATIENTS AND METHODS

IUdR was added to the previously studied regimen of continuous infusion 5-FU at 300 mg/m2/day for 5 days, HU 500 mg every 12 hours for 11 doses and radiotherapy 200 cGy/day for 5 days, all administered for 7 consecutive weeks to patients with malignant glioma. IUdR was administered as 5-day continuous intravenous infusion during weeks 1 and 4. The IUdR dose was changed in cohorts of patients. IUdR plasma concentrations were determined during weeks 1 and 4, and IUdR incorporation into the DNA of granulocytes was measured on weeks 2 and 5.

RESULTS

Two patients treated at the initial IUdR dose of 500 mg/m2/day developed grade 3 or 4 myelosuppression and mucositis. Additional dose levels of IUdR tested were 250 mg/m2/day and 125 mg/m2/day; at the latter dose, severe or life-threatening toxicity was seen in only 3 of 8 patients treated. IUdR incorporation into DNA of granulocytes was 10.5(+/- 2.3)% at an IUdR dose of 500 mg/m2/day but decreased to 0.76(+/- 0.3)% at 125 mg/m2/day. Similarly, IUdR plasma concentrations decreased from 436 (+/- 114) ng/ml to 99 (+/- 29) ng/ml.

CONCLUSIONS

The addition of IUdR to 5-FU and HU results in significant systemic toxicity necessitating limitation of the IUdR dose to 125 mg/m2/day. There is a significant biochemical interaction between IUdR, 5-FU and HU leading to increased IUdR incorporation into DNA and to substantial clinical toxicity. Further clinical studies to exploit this interaction at more feasible schedules may be useful.

Perioperative respiratory management in cardiac surgery

The perioperative respiratory care of the cardiac surgical patient can present many challenges to the caring physician that he or she may not see among the usual patient population. Knowledge of the effects of the heart-lung machine on pulmonary performance, awareness of the anatomic changes brought on by the surgeon, and consideration of the patient's baseline cardiac and pulmonary function need to be addressed so that the pulmonary problems that they present can be managed optimally.

The influence of respiratory acid-base status on adult pulmonary vascular resistance before and after cardiopulmonary bypass

Respiratory acid-base status has recently been shown to affect pulmonary vascular resistance (PVR) in adults following cardiac surgery. The purpose of this study was to examine what influence cardiopulmonary bypass has on the pulmonary vascular response to changes in respiratory acid-base status. Fifteen consecutive patients undergoing aortocoronary bypass were studied under general anesthesia both before and after cardiopulmonary bypass. Arterial PCO2 was manipulated by the addition of 5 percent carbon dioxide to the breathing circuit. Both before and after bypass, PVR increased significantly as PCO2 rose from 30 mm Hg to 50 mm Hg (p < 0.05). The PVR returned to baseline as PCO2 was returned to 30 mm Hg. These data suggest that increased PVR induced by hypercarbic acidemia is not simply a result of the effects of cardiopulmonary bypass on the pulmonary circulation. Instead, we conclude that respiratory acid-base status is an important determinant of adult PVR. We believe these data may be helpful in the treatment of mechanically ventilated patients, since patients are at particular risk of having abnormalities develop in respiratory acid-base status.

Protecting myocardial creatine kinase activity during reperfusion improves bioenergetics and contractile function

The exact mechanisms underlying reperfusion (RP) injury are unclear but are thought to involve toxic oxygen metabolites such as H2O2. The purpose of our study was to determine whether increasing endogenous catalase (CAT) stores would protect creatine kinase (CK) activity and improve bioenergetics and mechanical function during RP. Rats (n = 6/group) were pretreated with myristic acid (MA) or nothing 6 to 12 hr prior to cardiectomy. Hearts were Langendorff perfused and developed pressure (DP) was monitored during 25 min of 37 degrees C ischemia and 10 or 40 min of RP. CK activity was determined at baseline, end ischemia, and 40 min RP. CAT activity and H2O2 production was assayed at baseline, end ischemia, and 10 min RP. 31P NMR spectra were continuously acquired to determine ATP and phosphocreatine (PCr) concentrations. MA-pretreated hearts demonstrated elevated CAT stores (121 +/- 4%, P < 0.05). No H2O2 was produced during ischemia, and both groups generated significant but equal amounts of H2O2 at RP 10 (P < 0.001 vs preischemia (PI), P = NS between groups). By RP 40, MA-pretreated hearts recovered more DP than did control hearts (75 +/- 5% of PI vs 35 +/- 4% of PI, P < 0.001) and retained more CK activity as well (66 +/- 4% vs 52 +/- 2%, P < .05). PCr/ATP ratios of control hearts were abnormally elevated above baseline and that of MA hearts during RP (2.4 +/- 0.1 vs 1.85 +/- 0.08, P < 0.05 at RP 40).(ABSTRACT TRUNCATED AT 250 WORDS)

Mammographically detected breast cancer: location in women under 50 years old

The mammograms of 86 women under the age of 50 years with mammographically detected cancers were reviewed. Sixty-three of these cancers (73%) were found at the periphery of the breast as defined by a zone 1 cm wide beneath the subcutaneous fat or anterior to the retromammary fat. This finding is likely due to the geometric configuration of the breast. If the breast is hemispheric, then more than 50% of the volume of breast tissue lies within this zone in a large percentage of women. Furthermore, the contrasting adjacent fat likely improves the ability to perceive an abnormality. Interaction of the terminal ducts with chemicals contained within or produced by the fat is a much less likely reason for the high percentage of cancers in this zone. Radiologists should be aware of this phenomenon and pay particular attention to this zone.

Renal pseudoenlargement secondary to retroperitoneal liposarcoma

A case of renal pseudoenlargement caused by a large retroperitoneal mass is reported. An intravenous urogram showed apparent enlargement of the right kidney and a normal left kidney. Computed tomography showed a normal-sized right kidney. The discrepancy was due to magnification produced by marked anterior displacement of the right kidney by a retroperitoneal liposarcoma.

Breast cancer survival among women under age 50: is mammography detrimental?

Great uncertainty exists about the benefit of detecting breast cancer by mammography in women under 50 years of age. We have reviewed the survival of patients aged 49 years or less whose cancers were detected by mammography alone. 117 women under the age of 50 years were diagnosed with breast cancer between 1978 and 1991 based only on an abnormal mammogram. Ductal carcinoma in-situ (DCIS) was found in 47 (40%) of these women, whilst 70 (60%) had infiltrating ductal or infiltrating lobular carcinomas. During the same interval, 928 women in this age group presented with palpable breast cancer. DCIS was diagnosed in 82 (9%) of these women, whilst 846 (91%) had infiltrating carcinoma. Among the infiltrating cancers detected by mammography alone, 50% were stage I, whilst only 30% of the women with palpable cancers were stage I. Five-year survival for all mammographically detected cancer patients was 95%, whereas for women with palpable cancers the survival was 74% (p < 0.00005). If DCIS is not included, the corresponding survivals are 91% for mammographically detected infiltrating cancers and 72% for palpable infiltrating cancers. Only 1 woman who died among those with palpable cancer had had a mammogram before diagnosis. Our data contradict the suggestion that women under 50 are put at a survival disadvantage by undergoing mammography. We believe that investigators who have reported negative results in this age group must examine other causes for their results.

Safe intraaortic balloon pump placement through the ascending aorta using transesophageal ultrasound

Intraaortic balloon pumping salvages a substantial number of patients who fail to be weaned from cardiopulmonary bypass after an open heart operation. Patients with severe peripheral vascular disease may require ascending aortic balloon pump insertion. We describe a simple method of direct aortic puncture for intraaortic balloon pump placement using transesophageal ultrasound as a means of avoiding complications during insertion and documenting correct balloon position.

Continuous-infusion fluorodeoxyuridine with leucovorin and high-dose interferon: a phase II study in metastatic renal-cell cancer

A total of 25 patients with metastatic renal cancer were treated on a phase II protocol with 5 days of continuous-infusion fluorodeoxyuridine (FUDR), (0.1 mg/kg daily) together with high-dose oral leucovorin (100 mg 4 h) and daily x6 high-dose interferon-alpha 2b (30 x 10(6) IU/m2). Despite the good performance status of the patients and the inclusion of 14 previously untreated patients in the cohort, no response was observed among the 20 evaluable patients. Toxicities included high fever, moderate anemia, transient leukopenia, transient and mild elevations of transaminases, and moderate to severe nausea, vomiting, diarrhea, and mucositis. There were also two episodes each of confusion, fluid retention, and pancreatitis and one episode of increased creatinine levels. During the study three deaths occurred, two of which were possibly therapy-related. Despite previous reports of activity of FUDR in metastatic renal cancer, the present regimen cannot be recommended.

Oxygen metabolite effects on creatine kinase and cardiac energetics after reperfusion

Noninvasive 31P nuclear magnetic resonance measurements indicate that during the initial reperfusion phase myocardial tissue contents of phosphocreatine (PCr) recover rapidly, while ATP levels remain low and recover slowly. There is also a burst of H2O2 during the first 10 min of reperfusion, as indicated by the in vivo inactivation of catalase that occurs only when H2O2, and the inactivator 3-aminotriazole (AMT), are simultaneously present. Neither H2O2 production nor CK inactivation was discernable after ischemia alone. In excitable tissue the PCr and ATP pools are equilibrated by the enzyme creatine kinase (CK), but myocardial CK activity is decreased by 20% after reperfusion, though not by simple washout. Extrapolating from the well-known air sensitivity of CK, we find that limited exposure in vitro to small concentrations of H2O2 can markedly diminish CK activity. We postulate that failure of certain CK isoenzymes at energy-using termini may decouple the relative rates of PCr production and ATP regeneration and hence cause elevated PCr-to-ATP ratios. The assumptions of 1) CK equilibrium during the reperfusion period to calculate free ADP levels and 2) cardiac recovery deduced from the elevation of PCr levels may require reexamination.

Use of human recombinant erythropoietin to correct severe preoperative anemia

The risks of homologous blood transfusion are well known. Herein, we describe the successful preoperative use of human recombinant erythropoietin to correct severe anemia in a patient refusing transfusion. This case report emphasizes the important perioperative role human recombinant erythropoietin may play in the future.

Primed neutrophils injure rat lung through a platelet-activating factor-dependent mechanism

Bacterial lipopolysaccharide (LPS) promotes transient lung neutrophil sequestration. These LPS-primed neutrophils, when stimulated by an N-formyl peptide (FNLP), promote lung injury. We hypothesized that LPS-primed, FNLP-stimulated neutrophils promote lung injury through a platelet-activating factor (PAF)-dependent mechanism. Rats were pretreated with either saline or WEB2170, a PAF receptor antagonist (10 mg/kg po). One hour after pretreatment, rats were administered intraperitoneal LPS (salmonella typhimurium lipopolysaccharide, 500 micrograms/kg) followed 6 hr later by intravenous FNLP (250 micrograms/kg infused over 30 min). Two hours after the initiation of FNLP infusion, rats were sacrificed and assays were performed to measure: (1) lung neutrophil sequestration with myeloperoxidase (MPO) activity; (2) circulating neutrophil activation with nitroblue tetrazolium (NBT) staining, and (3) lung microvascular leak with 125I-albumin flux. We found that lung myeloperoxidase, circulating neutrophil NBT staining, and lung 125I-albumin flux were increased (P less than 0.05) in saline-pretreated LPS/FNLP rats, relative to control. While lung MPO remained increased (P less than 0.05) in WEB2170-pretreated LPS/FNLP rats, circulating neutrophil NBT and lung 125I-albumin flux were decreased (P less than 0.05) relative to those in saline-pretreated rats. We conclude that PAF mediates LPS/FNLP-induced neutrophil activation and lung injury, but is independent from lung neutrophil sequestration. Thus, lung neutrophil sequestration does not inevitably produce lung injury. Rather, neutrophils can accumulate in the lung without causing lung injury if neutrophil activation can be blocked.

Bronchial anomaly of the right upper lobe

This case report presents a rare anomaly of right upper lobe bronchial anatomy. During routine right upper lobe resection for carcinoma, a common right upper and middle lobe bronchus was found. The resection was completed as a right upper and middle bilobectomy. Knowledge of this uncommon variant was beneficial in performing the pulmonary resection. A review of the literature is presented.

Improved cannulation method for extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation has been shown to be useful for patients in reversible cardiogenic shock. Effective arterial cannulation techniques for infants have been developed that are simple to use and require minimal subsequent vascular repair or reconstruction after removal. Groin cannulation in adults frequently requires bidirectional arterial cannulation to ensure adequate distal perfusion as well as frequent complex arterial repairs after discontinuation. We describe a simple arterial cannulation technique using a single right-angle, high-flow arterial cannula. With this technique adequate bidirectional arterial perfusion is maintained with a single arterial cannula while the need for vascular repairs or reconstruction is minimized.

Reversible lung neutrophil accumulation can cause lung injury by elastase-mediated mechanisms

Neutrophils have been implicated in multiple models of end-organ injury. The purposes of this study were to determine whether (1) a sublethal septic insult promotes lung neutrophil accumulation, (2) this pulmonary neutrophil accumulation is reversible, (3) these accumulated neutrophils can be activated to injure lung, and (4) this pulmonary neutrophil accumulation obligates lung injury. Rats were administered low-dose endotoxin, 500 micrograms/kg, intraperitoneally, and at 6 or 12 hours, lungs were harvested and assayed for myeloperoxidase, a marker of neutrophil accumulation, and iodine 125-labeled albumin uptake, a marker of lung injury. A second set of rats were administered low-dose endotoxin and at 6 or 12 hours were given a neutrophil activator formyl-norleucyl-leucyl-phenylalanine (FNLP) 250 micrograms/kg, intravenously. At 8 or 14 hours, lungs were harvested and assayed for 125I-labeled albumin uptake. A third set of rats were administered low-dose endotoxin, and at 5 1/2 hours 30 minutes before FNLP administration, they were given a neutrophil elastase inhibitor, methyoxysuccinyl-L-alanine-L-alanine-L-proline-L-valine-chlorometh yl ketone, 2.5 mg/kg, intraperitoneally. At 6 hours rats were given FNLP, and at 8 hours lungs were harvested and assayed for 125I-labeled albumin uptake. The following results were obtained: (1) low-dose endotoxin caused a transient increase (p less than 0.05) in lung neutrophil accumulation at 6 hours, which was resolved by 12 hours; (2) lung 125I-labeled albumin uptake was unchanged both 6 and 12 hours after isolated low-dose endotoxin administration; (3) neutrophil activation increased (p less than 0.05) lung 125I-labeled albumin uptake when imposed 6 but not 12 hours after low-dose endotoxin administration; and (4) elastase inhibition decreased (p less than 0.05) the lung 125I-labeled albumin uptake promoted by endotoxin and FNLP. We conclude that sublethal endotoxemia causes a reversible lung neutrophil accumulation and that this lung neutrophil accumulation does not obligate lung injury; but activation of these accumulated neutrophils can promote lung injury, and this neutrophil-associated lung injury is mediated in part by neutrophil elastase.

Reversal of protamine-induced catastrophic pulmonary vasoconstriction by prostaglandin E1

A case of catastrophic pulmonary vasoconstriction occurring after cardiopulmonary bypass after protamine reversal of heparin treated successfully with intravenous prostaglandin E1 is reported. Systemic hypotension was counteracted by epinephrine given through the left atrium. Protamine-heparin reactions are reviewed and a pathophysiological mechanism for the beneficial effect seen with prostaglandin E1 is proposed.