Paradoxical effects of cigarette smoke and COPD on SARS-CoV-2 infection and disease

BACKGROUND

How cigarette smoke (CS) and chronic obstructive pulmonary disease (COPD) affect severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection and severity is controversial. We investigated the effects of COPD and CS on the expression of SARS-CoV-2 entry receptor ACE2 in vivo in COPD patients and controls and in CS-exposed mice, and the effects of CS on SARS-CoV-2 infection in human bronchial epithelial cells in vitro.

METHODS

We quantified: (1) pulmonary ACE2 protein levels by immunostaining and ELISA, and both ACE2 and/or TMPRSS2 mRNA levels by RT-qPCR in two independent human cohorts; and (2) pulmonary ACE2 protein levels by immunostaining and ELISA in C57BL/6 WT mice exposed to air or CS for up to 6 months. The effects of CS exposure on SARS-CoV-2 infection were evaluated after in vitro infection of Calu-3 cells and differentiated human bronchial epithelial cells (HBECs), respectively.

RESULTS

ACE2 protein and mRNA levels were decreased in peripheral airways from COPD patients versus controls but similar in central airways. Mice exposed to CS had decreased ACE2 protein levels in their bronchial and alveolar epithelia versus air-exposed mice. CS treatment decreased viral replication in Calu-3 cells, as determined by immunofluorescence staining for replicative double-stranded RNA (dsRNA) and western blot for viral N protein. Acute CS exposure decreased in vitro SARS-CoV-2 replication in HBECs, as determined by plaque assay and RT-qPCR.

CONCLUSIONS

ACE2 levels were decreased in both bronchial and alveolar epithelial cells from COPD patients versus controls, and from CS-exposed versus air-exposed mice. CS-pre-exposure potently inhibited SARS-CoV-2 replication in vitro. These findings urge to investigate further the controversial effects of CS and COPD on SARS-CoV-2 infection.

Paradoxical effects of cigarette smoke and COPD on SARS-CoV2 infection and disease

Introduction

How cigarette smoke (CS) and chronic obstructive pulmonary disease (COPD) affect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severity is controversial. We investigated the protein and mRNA expression of SARS-CoV-2 entry receptor ACE2 and proteinase TMPRSS2 in lungs from COPD patients and controls, and lung tissue from mice exposed acutely and chronically to CS. Also, we investigated the effects of CS exposure on SARS-CoV-2 infection in human bronchial epithelial cells.

Methods

In Cohort 1, ACE2-positive cells were quantified by immunostaining in FFPE sections from both central and peripheral airways. In Cohort 2, we quantified pulmonary ACE2 protein levels by immunostaining and ELISA, and both ACE2 and TMPRSS2 mRNA levels by RT-qPCR. In C57BL/6 WT mice exposed to air or CS for up to 6 months, pulmonary ACE2 protein levels were quantified by triple immunofluorescence staining and ELISA. The effects of CS exposure on SARS-CoV-2 infection were evaluated after 72hr in vitro infection of Calu-3 cells. After SARS-CoV-2 infection, the cells were fixed for IF staining with dsRNA-specific J2 monoclonal Ab, and cell lysates were harvested for WB of viral nucleocapsid (N) protein. Supernatants (SN) and cytoplasmic lysates were obtained to measure ACE2 levels by ELISA.

Results

In both human cohorts, ACE2 protein and mRNA levels were decreased in peripheral airways from COPD patients versus both smoker and NS controls, but similar in central airways. TMPRSS2 levels were similar across groups. Mice exposed to CS had decreased ACE2 protein levels in their bronchial and alveolar epithelia versus air-exposed mice exposed to 3 and 6 months of CS. In Calu3 cells in vitro, CS-treatment abrogated infection to levels below the limit of detection. Similar results were seen with WB for viral N protein, showing peak viral protein synthesis at 72hr.

Conclusions

ACE2 levels were decreased in both bronchial and alveolar epithelial cells from uninfected COPD patients versus controls, and from CS-exposed versus air-exposed mice. CS-pre-treatment did not affect ACE2 levels but potently inhibited SARS-CoV-2 replication in this in vitro model. These findings urge to further investigate the controversial effects of CS and COPD on SARS-CoV2 infection.

Hypoxia-inducible VEGF gene delivery to ischemic myocardium using water-soluble lipopolymer

Therapeutic angiogenesis with gene encoding vascular endothelial growth factor (VEGF) is a new potential treatment in cardiovascular disease. However, unregulated VEGF-mediated angiogenesis has the potential to promote tumor growth, accelerate diabetic proliferative retinopathy, and promote rupture of atherosclerotic plaque. To be safe and effective, gene therapy with VEGF must be regulated. To limit the risk of pathological angiogenesis, we developed a hypoxia-inducible VEGF gene therapy system using the erythropoietin (Epo) enhancer and water-soluble lipopolymer (WSLP). pEpo-SV-VEGF or pSV-VEGF-Epo was constructed by insertion of the Epo enhancer upstream of the Simian Virus 40 (SV40) promoter or downstream of the poly(A) signal of pSV-VEGF. In vitro transfection showed that pEpo-SV-VEGF, not pSV-VEGF-Epo, induced the VEGF expression in hypoxic cells. In addition, the VEGF protein, which was produced from the Epo-SV-VEGF-transfected and hypoxia-incubated cells, was able to enhance the proliferation of the endothelial cells. Injection of the pEpo-SV-VEGF/WSLP complex showed that the expression of VEGF was induced in ischemic myocardium, compared to normal myo-cardium. Therefore, with the localized induction of VEGF and the low cytotoxicity of WSLP, the pEpo-SV-VEGF/WSLP system may be helpful to eventually treat ischemic heart disease.

Improved biochemical preservation of heart slices during cold storage

BACKGROUND

Development of myocardial preservation solutions requires the use of whole organ models which are animal and labor intensive. These models rely on physiologic rather than biochemical endpoints, making accurate comparison of the relative efficacy of individual solution components difficult. We hypothesized that myocardial slices could be used to assess preservation of biochemical function during cold storage.

MATERIALS AND METHODS

Whole rat hearts were precision cut into slices with a thickness of 200 microm and preserved at 4 degrees C in one of the following solutions: Columbia University (CU), University of Wisconsin (UW), D5 0.2% normal saline with 20 meq/l KCL (QNS), normal saline (NS), or a novel cardiac preservation solution (NPS) developed using this model. Myocardial biochemical function was assessed by ATP content (etamoles ATP/mg wet weight) and capacity for protein synthesis (counts per minute (cpm)/mg protein) immediately following slicing (0 hours), and at 6, 12, 18, and 24 hours of cold storage. Six slices were assayed at each time point for each solution. The data were analyzed using analysis of variance and are presented as the mean +/- standard deviation.

RESULTS

ATP content was higher in the heart slices stored in the NPS compared to all other solutions at 6, 12, 18 and 24 hours of cold storage (p < 0.05). Capacity for protein synthesis was higher in the heart slices stored in the NPS compared to all other solutions at 6, 12, and 18 hours of cold storage (p < 0.05). CONCLUSIONS This myocardial slice model allows the rapid and efficient screening of cardiac preservation solutions and their components using quantifiable biochemical endpoints. Using this model, we have developed a novel preservation solution which improves the biochemical function of myocardial slices during cold storage.

Water-soluble lipopolymer as an efficient carrier for gene delivery to myocardium

Water-soluble lipopolymer (WSLP), which consisted of polyethylenimine (PEI, 1800 Da) and cholesterol, was characterized as a gene carrier to smooth muscle cells and myocardium. Acid-base titration showed that WSLP had a proton-buffering effect. The size of WSLP/plasmid DNA (pDNA) complex was around 70 nm. WSLP/pDNA complex was transfected to A7R5 cells, a smooth muscle cell line. WSLP showed the highest transfection at a 40/1 N/P ratio. WSLP has higher transfection efficiency than PEI (1800 and 25 000 Da), SuperFect, and lipofectamine. In addition, WSLP has less cytotoxicity than PEI (25 000 Da), SuperFect, and lipofectamine. Since WSLP has cholesterol moiety, it may utilize cellular cholesterol uptake pathway, in which low-density lipoprotein (LDL) is involved. An inhibition study with free cholesterol or low-density lipoprotein (LDL) showed that transfection was inhibited by cholesterol or LDL, suggesting that WSLP/pDNA complex is transfected to the cells through the cholesterol uptake pathway. To evaluate the transfection efficiency to myocardium, WSLP/pDNA complex was injected into the rabbit myocardium. WSLP showed higher transfection than PEI and naked pDNA. WSLP expressed the transgene for more than 2 weeks. In conclusion, WSLP is an efficient carrier for local gene transfection to myocardium, and useful in in vivo gene therapy.

Augmentation of myocardial transfection using TerplexDNA: a novel gene delivery system

Gene therapy is a potential new strategy for the treatment of cardiovascular disease. The most efficacious method of gene delivery remains a key hurdle to effective gene therapy. We present the application of a novel, nonviral gene delivery system (TerplexDNA) to augment myocardial transfection. The hearts of New Zealand white rabbits were injected with reporter genes, luciferase cDNA or beta-galactosidase cDNA, either as naked plasmid DNA or plasmid DNA complexed with stearyl-poly(L-lysine)-low density lipoprotein (TerplexDNA). Three day left heart myocardial cell lysates produced 44571 +/- 8730 RLU (RLU = total light units/mg protein) for the TerplexDNA luciferase rabbits versus 1638 +/- 567 RLU for the naked luciferase rabbits (P = 0.002). Thirty days after injection, myocardial lysates produced 677 +/- 52 RLU for the TerplexDNA luciferase hearts versus 18 +/- 3 RLU for the naked luciferase hearts (P = 0.002). Histologic analysis of the hearts transfected with beta-galactosidase showed that TerplexDNA increased the area and depth of transfection compared with the naked plasmid DNA alone. The hearts of Sprague-Dawley rats were injected in a similar fashion and analyzed at 1, 3, 5, 10, 15, 25 and 30 days after injection. The naked luciferase injected hearts showed transient elevation of luciferase activity to day 5 but fell back to baseline levels after that time-point. The TerplexDNA luciferase injected hearts had significantly elevated luciferase activity to 30 days. The Terplex gene delivery system significantly augments myocardial transfection compared with a naked plasmid DNA system alone. The advantage in transfection efficiency appears to be related to the unique properties of the TerplexDNA carrier molecule. The TerplexDNA delivery system represents a novel means to augment transfection of the myocardium.

Effect of a resident self-study and presentation program on performance on the thoracic surgery in-training examination

BACKGROUND

In this study we examine whether conversion from a didactic lecture format to a resident self-study and presentation program can improve performance on the Thoracic Surgery In-Training Examination (TSITE).

METHODS

During the first 5 years, educational conferences were didactic lectures delivered by the attending thoracic surgery staff (group 1, n = 9 residents). During the second 5 years, residents prepared and delivered reviews from major textbook sources (group 2, n = 9 residents). Scores on the American Board of Surgery In-Training Examination (ABSITE) as a chief resident in general surgery were analyzed using one-way analysis of variance to assess fund of knowledge and test-taking skills prior to thoracic surgery training for the two groups. Scores on the TSITE during the first and second years of thoracic surgery training were recorded for each resident and analyzed using a paired t test. The data are expressed as the mean +/- standard deviation.

RESULTS

Eighteen thoracic surgery residents over a 10-year period were involved in the study. ABSITE scores as a chief resident in general surgery did not differ between the two groups. Residents in group 1 improved their percentile rank from the first to the second year by a mean of 11%+/-12%, whereas those in group 2 improved their scores by a mean of 31%+/-21% (P < 0.05).

CONCLUSIONS

When compared with a didactic lecture format, a resident self study and presentation program improves performance on the Thoracic Surgery In-Training Examination. This improvement in performance typically manifests during the second year of thoracic surgery training.

Interleukin-18 production following murine cardiac transplantation: correlation with histologic rejection and the induction of INF-gamma

Interleukin-18 (IL-18) and IL-12 have been shown to play an important role in the induction of interferon-gamma (IFN-gamma). IFN-gamma induces the proliferation of T cells and natural killer (NK) cells and augments the Th1 immune cascade. The role of IL-18 and IL-12 in the induction of IFN-gamma following allogeneic heart transplantation has not been described. We sought to characterize the IL-12 and IL-18 response to murine allogeneic heart transplantation, particularly with respect to IFN-gamma production and histologic transplant rejection. Forty-eight heterotopic heart transplants were performed in two groups of mice: syngeneic C3H/HeN to C3H/HeN mice and allogeneic BALB/C to C3H/HeN mice. Transplants were followed out to 2, 6, 10, and 14 days. Six transplants were performed in each group. Serum and splenic samples were used to evaluate the cytokine response by ELISA. Explanted heart tissue was processed for evidence of histologic rejection, and RT-PCR was performed to evaluate the IL-12, IL-18, and IFN-gamma signal qualitatively. Analysis of variance (ANOVA), Fisher's projected least significant difference (PLSD) was used for statistical analysis. Transplant rejection occurred in the allogeneic group histologically by day 6 and clinically by day 10. Serum IFN-gamma levels rose significantly by day 6 in the allogeneic group and then continued to rise in the splenocyte cultures. Serum IL-18 also rose significantly in the allogeneic group at day 6 compared with syngeneic group. RT-PCR revealed that the allogeneic tissue contained an increased signal for IL-12, IL-18, and IFN-gamma beginning at day 6 and peaking at day 10 after transplant. Beginning 6 days after transplantation, IL-12 and IL-18 appear to play a significant role in the induction of IFN-gamma in allogeneic heart transplants.

Coronary artery bypass grafting with cardiopulmonary bypass versus off-pump cardiopulmonary bypass grafting: does eliminating the pump reduce morbidity and cost?

BACKGROUND

Cardiopulmonary bypass (CPB) may contribute to the complications and cost of coronary artery bypass grafting (CABG). Off-pump CABG (OPCAB) allows coronary revascularization without CPB. We hypothesized that OPCAB provides satisfactory graft patency while reducing complications and cost compared with CABG with CPB.

METHODS

We prospectively followed 80 patients undergoing CABG: 40 patients undergoing OPCAB and 40 patients undergoing CABG with CPB. OPCAB patients underwent angiography within 48 hours of surgery to determine early graft patency. Incidence of complications, length of stay, and costs were recorded for each patient. The influence of the number of vessels bypassed was analyzed.

RESULTS

OPCAB patients (n = 40) underwent grafting of 2.7 +/- 0.7 vessels per patient compared with 3.6 +/- 0.8 vessels per patient in the CABG with CPB group (n = 40) (p < 0.0001). Angiography demonstrated 105 of 108 (97%) of grafts were patent in the OPCAB group. Incidence of complications, length of stay, and costs did not differ between the OPCAB and CABG with CPB groups. Number of vessels grafted showed a positive correlation to total costs in both groups.

CONCLUSIONS

While OPCAB provided satisfactory early graft patency, there was no significant difference between OPCAB and CABG with CPB with regard to cost, length of stay, or incidence of complications. In this study, eliminating CPB did not reduce morbidity or cost after CABG.

Functional outcome and survival after pharyngolaryngoesophagectomy for cancer

BACKGROUND

Surgical resection of the larynx, hypopharynx and cervical esophagus, or pharyngolaryngoesophagectomy (PLE), with pharyngogastric anastomosis (PGA) offers a means of controlling local and regional carcinoma of the upper aerodigestive tract (UADT). We reviewed our experience with PLE for carcinoma of the UADT to evaluate functional outcome and survival.

METHODS

Patients undergoing PLE from 1986 through 1999 were reviewed. Survivors completed questionnaires which graded their level of function and voice rehabilitation. Gastric emptying studies were performed with rates compared with normal controls. Survival curves were generated using the Kaplan-Meier method.

RESULTS

Thirty-one patients underwent PLE during the study period. Twenty-nine patients had squamous cell carcinoma. Operative mortality was 0%. Thirty-day mortality was 9.6%. There were 2 anastomotic leaks (6.4%). All survivors reported normal ability to complete activities of daily living. Voice rehabilitation was acceptable in 7 of 10 survivors. Positive surgical margins resulted in decreased survival (P = 0.03). No other patient demographic or management variable altered survival. One-year, 5-year, and 10-year survival rates were 67%, 40%, and 18%, respectively.

CONCLUSION

PLE with PGA for carcinoma of the UADT may be performed with low morbidity and mortality. Functional patient outcomes including gastric emptying, activities of daily living, and voice rehabilitation are acceptable.

Improved biochemical preservation of lung slices during cold storage

BACKGROUND

Development of lung preservation solutions typically requires whole-organ models which are animal and labor intensive. These models rely on physiologic rather than biochemical endpoints, making accurate comparison of the relative efficacy of individual solution components difficult. We hypothesized that lung slices could be used to assess preservation of biochemical function during cold storage.

MATERIALS AND METHODS

Whole rat lungs were precision cut into slices with a thickness of 500 microm and preserved at 4 degrees C in the following solutions: University of Wisconsin (UW), Euro-Collins (EC), low-potassium-dextran (LPD), Kyoto (K), normal saline (NS), or a novel lung preservation solution (NPS) developed using this model. Lung biochemical function was assessed by ATP content (etamol ATP/mg wet wt) and capacity for protein synthesis (cpm/mg protein) immediately following slicing (0 h) and at 6, 12, 18, and 24 h of cold storage. Six slices were assayed at each time point for each solution. The data were analyzed using analysis of variance and are presented as means +/- SD.

RESULTS

ATP content was significantly higher in the lung slices stored in NPS compared with all other solutions at each time point (P < 0.0001). Protein synthesis was significantly higher in the lung slices stored in NPS compared with all other solutions at 6, 12, and 18 h of preservation (P < 0.05).

CONCLUSIONS

This lung slice model allows the rapid and efficient screening of lung preservation solutions and their components using quantifiable biochemical endpoints. Using this model, we have developed a novel solution that improves the biochemical preservation of lung slices during cold storage.

Aprotinin preserves myocardial biochemical function during cold storage through suppression of tumor necrosis factor

OBJECTIVE

Inflammatory cytokines, particularly tumor necrosis factor, contribute to myocardial dysfunction after ischemia-reperfusion injury. Aprotinin may improve outcomes in cardiac surgery through suppression of inflammatory mediators. We hypothesized that aprotinin may exert its beneficial effects through suppression of tumor necrosis factor alpha.

METHODS

Adult rat hearts were precision cut into slices with a thickness of 200 microm and stored in crystalloid cardioplegic solution alone or with one of the following additions: aprotinin or tumor necrosis factor alpha, aprotinin plus tumor necrosis factor alpha, a monoclonal antibody to tumor necrosis factor alpha, or a polyclonal antibody to the tumor necrosis factor alpha receptor. Myocardial biochemical function was assessed by adenosine triphosphate content and capacity for protein synthesis immediately after slicing (0 hours) and after 2, 4, and 6 hours of storage at 4 degrees C. The content of tumor necrosis factor alpha was measured by an enzyme-linked immunosorbent assay. Six slices were assayed at each time point for each solution. The data were analyzed by analysis of variance and are expressed as the mean +/- standard deviation.

RESULTS

When stored in cardioplegic solution containing aprotinin, the heart slices demonstrated (1) an increase in adenosine triphosphate content and protein synthesis (P <.0001), (2) a decrease in intramyocardial generation of tumor necrosis factor alpha (P </=.0311), and (3) a decrease in uptake of tumor necrosis factor alpha into the myocardium (P </=.002) compared with storage in cardioplegic solution alone. The presence of an antibody to tumor necrosis factor alpha or an antibody to the tumor necrosis factor alpha receptor in cardioplegic solution increased intramyocardial adenosine triphosphate content and protein synthesis (P <.0001).

CONCLUSIONS

Aprotinin preserves myocardial biochemical function during cold storage. This preservation of biochemical function is mediated through suppression of the release, uptake, and activity of tumor necrosis factor alpha.

Avoidance of cellular blood product transfusions in LVAD recipients does not prevent HLA allosensitization

BACKGROUND

Transfusion of cellular blood products during left ventricular assist device (LVAD) implantation has been associated with HLA allosensitization, resulting in the need for a negative prospective cross-match and prolonged transplant waiting times. In order to prevent this risk, we developed a protocol to avoid transfusion of cellular blood products.

METHODS

The protocol included preoperative patient stabilization, perioperative recombinant erythropoietin and blood conservation strategies, and postoperative monitoring of mixed venous oxygen saturation (SVO2) to assure adequate peripheral oxygen delivery. Panel reactive antibody (PRA) was measured in all patients pre and post LVAD placement to assess HLA sensitization.

RESULTS

Seven consecutive patients underwent LVAD implantation without transfusion of blood or platelets, one of whom expired perioperatively. Mean hematocrit was 35.2% preoperatively, and 21.8% postoperatively, reaching a nadir of 20.2%. Postoperative SVO2 was >60% in all patients. In the six survivors, mean hematocrit reach 24.3%, 27.3%, and 33.0% by postoperative day seven, fourteen, and thirty, respectively. PRA in three patients was 0% preoperatively and remained 0% until transplantation after 33, 34, and 50 days of support. In two patients, preoperative PRA was 7% and 17%, dropped to 3% and 0% after thirty days, then progressively rose to 96% and 100% after 60 and 90 days, respectively. In one other patient, preoperative PRA was 0%, remained at 0% after thirty days, then rose to 96% by 60 days.

CONCLUSIONS

Avoiding transfusion of cellular blood products in LVAD recipients is safe and well tolerated, but does not universally protect from HLA allosensitization. Other factors may also produce sensitization, such as immunogenic components of the LVAD, soluble antigen in fresh frozen plasma, or latent sensitization which is not initially evident in critically ill and possibly anergic patients.

Ruptured sinus of Valsalva aneurysm in a patient with autosomal dominant polycystic kidney disease

Images

Incidence and histologic characteristics of blebs in patients with abdominal aortic aneurysms

PURPOSE

Aortic blebs-focal outpouchings within aortic aneurysms-may contribute to their eventual rupture. In this study we determine the incidence of aortic blebs and describe their microscopic features.

METHODS

Computed tomographic scans of the abdominal aorta were obtained in 188 patients with aortic diameters measuring > or = 3 cm and were independently evaluated by a radiologist. The number and location of blebs were recorded, and each was measured with calipers. Sixteen blebs, with an adjacent uninvolved aneurysmal segment of aorta, and tissue from two patients with ruptured aneurysms were examined by light microscopy and immunohistochemical analysis. Specimens from six blebs and five aneurysms were examined for alpha 1 (I) procollagen messenger RNA by in situ hybridization.

RESULTS

Twenty blebs, ranging in size from 5 to 30 mm (mean, 12 +/- 7 mm), were detected in 11% (20 of 188) of computed tomographic scans. Blebs were observed in 10% (11 of 111) of patients with aortic diameters between 3.0 and 4.9 cm, 10% (6 of 61) of patients with aneurysms between 5.0 and 6.9 cm, and 19% (3 of 16) of patients with aortic diameters > or = 7 cm. Histologically, the major difference between the aneurysmal aortic wall and blebs was found in the media. In aneurysmal aortas, the media consisted of multiple layers of fragmented elastic lamellae, whereas the number of elastic tissue elements along the circumference of the blebs progressively decreased; only a few isolated fragments of elastic tissue were present at the apices. Histologic evidence of rupture was evident in two specimens. A chronic inflammatory cell infiltrate composed of T and B lymphocytes, plasma cells, and macrophages, common to both the aneurysmal and the blebs, was most prominent in the adventitia of aneurysmal tissue, but involved both the media and adventitia of the blebs. In situ hybridization demonstrated the presence of alpha 1 (I) procollagen messenger RNA in four of the five aneurysm segments that were evaluated, compared with only one of six blebs.

CONCLUSIONS

Blebs were discovered in aneurysms of all sizes; their frequency appeared to be unrelated to aneurysm size. The presence of inflammatory cell infiltrates and absence of alpha 1 (I) procollagen messenger RNA in five of six blebs suggest that a local imbalance of matrix degradation and repair plays a role in the cause of these lesions. Attenuation of the aortic wall accompanying the formation of blebs may predispose these sites to rupture.

Long-term results of cardiac transplantation in patients older than sixty years. UTAH Cardiac Transplant Program

Advanced age has traditionally been a contraindication to cardiac transplantation. We have, however, offered cardiac transplantation to patients older than 60 years with end-stage heart failure if they were otherwise acceptable candidates. From 1985 to 1994, 527 patients underwent cardiac transplantation. Among these patients, 101 were older than 60 years at transplantation. The mean follow-up of this group is 6 years. Patients older than 60 years had significantly fewer rejection episodes per patient than those who were younger than 60 years at transplantation (1.9 +/- 1.3 vs 2.6 +/- 1.8, p = 0.009). No difference in the number of infectious complications per patient was detected between the two groups. Both short-term and long-term survival after transplantation were significantly lower for patients who were older than 60 years at transplantation than for younger patients (p < 0.05). The 6-year actuarial survival after transplantation for patients older than 60 years was 54% compared with 72% for patients younger than 60 years at transplantation (p < 0.05). Patients older than 60 years at transplantation were more likely to die of infectious complications or malignant disease after transplantation (p < 0.05). We believe caution is warranted in offering cardiac transplantation to patients older than 60 years. This group of patients should be carefully observed for the development of potentially life-threatening infectious complications or new malignant tumors after transplantation.

Prospective evaluation of peripheral vascular disease in heart transplant recipients

PURPOSE

Retrospective reviews suggest that the progression of peripheral vascular disease (PVD) may be accelerated in heart transplant recipients. This study was undertaken to determine the incidence and to identify those risk factors that may be associated with the development or progression of PVD in these patients.

METHODS

Between January 1990 and December 1993 a prospective vascular screening protocol including abdominal ultrasonography, Doppler-derived ankel-brachial pressure indexes (ABI), and carotid artery duplex imaging was added to the routine preoperative and annual postoperative evaluation of 239 heart transplant recipients.

RESULTS

Thirty-one significant vascular lesions were detected in 10% (24 of 239) of patients 52 +/- 9 years of age at a mean of 3.2 years after transplant. The distribution of lesions included carotid artery stenosis (11), femoropopliteal occlusive disease (10), aortoiliac occlusive disease (five), aortic aneurysm (four), and renal artery stenosis in one patient. Revascularization procedures were performed in 12 (50%) patients (carotid endarterectomy (four), aortobifemoral bypass grafting (three), abdominal aortic aneurysm repair (two), transluminal angioplasty (two), splenorenal bypass (one), and femorotibial bypass grafting (one)). One patient with diabetes mellitus (DM) was found to have noncompressible vessels during pretransplant evaluation. An additional 26 patients (11%), seven with DM, had noncompressible vessels in the lower extremities during the follow-up period. Logistic regression analysis revealed that the development of posttransplant PVD was associated with smoking (p < 0.05) and ischemic cardiomyopathy as an indication for transplantation (p < 0.05). The development of noncompressible vessels was associated with younger age (p < 0.05) and the presence of diabetes (p < 0.05).

CONCLUSION

Posttransplant peripheral vascular disease occurred in 10% of heart transplant recipients and is associated with pretransplant ischemic cardiomyopathy and smoking. A previously unrecognized subgroup of patients who have noncompressible vessels after operation is described. If the long-term survival of the heart transplant recipient is to be improved, routine follow-up to identify and treat those patients at greater risk appears justified.

The high risk heart donor: potential pitfalls

BACKGROUND

The use of potentially infected donor hearts has been advocated to extend the supply of available hearts for transplantation.

METHODS

To determine whether bacterial transmission from donor to recipient can occur with heart transplantation, we reviewed our experience with the 347 patients who received 360 heart transplants in the Utah Transplant Affiliated Hospitals from 1988 to 1993.

RESULTS

During this time, nineteen donors had positive blood cultures before harvest. Sixteen donors had gram-positive bacteremia: Staphylococcus epidermidis (n = 9), Staphylococcus aureus (n = 5), streptococcus (n = 2). Two donors had gram-negative bacteremia: serratia (n = 1) and acinetobacter (n = 1). One donor had blood cultures positive for both Escherichia coli and streptococcus. Infectious complications occurred in two of three recipients who received a heart from a donor with gram-negative bacteremia: Escherichia coli endocarditis, mediastinitis, sepsis and death in one, and serratia sepsis and mediastinitis in another. In each case the organisms and sensitivities were identical between donor and recipient. No infectious complications related to the donor heart occurred among the 16 recipients who received hearts from donors with gram-positive bacteremia.

CONCLUSIONS

(1) Bacterial transmission from donor heart to recipient can occur, (2) bacterial transmission appears to be more common with gram-negative organisms, and (3) infection of the recipient with a gram-negative organism from the donor heart is associated with significant morbidity and mortality.

Cellular origin and rate of endothelial cell coverage of PTFE grafts

To determine the origin, cell type present, and rate of endothelial cell coverage of PTFE grafts, 5-cm segments of 4-mm-diameter, 60-microns PTFE grafts were implanted end-to-end bilaterally in the carotid arteries of greyhound dogs. An external jugular vein wrap was applied to the outer surface of one of the PTFE grafts; the contralateral PTFE graft, which was unwrapped, served as its control. Two dogs each were sacrificed at 3, 5, 7, 14, 21, 28, and 35 days postimplantation. Anastomotic endothelial ingrowth was analyzed using scanning electron microscopy. Microvessel ingrowth was documented in longitudinal H&E sections. Cell identity was established by immunohistochemistry with factor VIII antibody, Ulex europaes, leukocyte common antigen, and antibodies to alpha-actin, desmin, vimentin, and basic fibroblast growth factor. All grafts were patent at the time of harvest. Endothelial cell migration from the native artery adjacent to the anastomosis commenced at 7 days, extended to 5 mm beyond the proximal and distal anastomoses by 14 days and to 1.0 cm by 35 days. Endothelialization of the mid-portion of the wrapped grafts occurred via microvessel ingrowth, a process which began at 7 days. Microvessels reached the luminal surface by 28 days and an endothelial cell monolayer was established by 35 days. Wrapping the external surface of the graft with vein increased the rate of graft healing. Basic fibroblast growth factor was detectable by immunohistochemistry at the vein wrap-graft interface in the first 14 days.

The effects of improved hemodynamics on aortic dimensions in patients undergoing heart transplantation

PURPOSE

Retrospective studies have demonstrated an accelerated growth rate of abdominal aortic aneurysms in heart transplant patients. This prospective study was undertaken to define the relationship between cardiac hemodynamics and posttransplant aortic dilation.

METHODS

Sixty-eight patients undergoing heart (n = 60) or heart-lung (n = 8) transplantation were prospectively evaluated with abdominal ultrasonography before transplantation and annually after transplantation. Risk factors implicated in aneurysm growth, including age, indication for transplantation, immunosuppression, posttransplantation hypertension, and abdominal aortic dimension before transplantation were recorded. All patients underwent annual coronary artery catheterization and multiple gated acquisition scanning.

RESULTS

Thirty-seven patients (54%) had no change in aortic diameter after transplantation (pretransplantation and posttransplantation diameter = 1.8 +/- 0.3 cm), over a mean follow-up period of 28 +/- 14 months. In the remaining 31 (46%) patients, aortic diameter increased by 0.5 +/- 0.6 cm over 31 +/- 15 months (p < 0.05). Four (6%) of these 31 patients had abdominal aortic aneurysms (mean aortic diameter = 5.0 +/- 0.8 cm). The mean increase in aortic diameter among these 4 patients was 1.8 +/- 0.2 cm (annual rate of growth = 0.96 +/- 0.3 cm/year). Patients experiencing an increase in aortic dimension after transplantation had significantly lower (p < 0.005) pretransplantation ejection fractions (17.1% +/- 10.5% vs 28.6% +/- 18.1%) and, as a consequence, significantly greater (p < 0.05) increases in their ejection fractions after transplantation compared with patients with stable aortic dimensions (42.7% +/- 12.6% vs 31.8% +/- 18.0%).

CONCLUSIONS

Of 68 heart transplant patients prospectively evaluated, aortic diameter increased in 31 (46%); new aneurysms developed in four of these patients. Greater incremental increases in cardiac ejection fraction were significant correlates with aortic enlargement.

Putative vascular endothelial cell chemotactic factors: comparison in a standardized migration assay

While a number of chemoattractants of vascular endothelial cells have now been identified in vitro, differences in methodology preclude comparisons of substances evaluated in different assays. Here, we report a standardized chemotactic assay in which the migration of calf pulmonary artery endothelial cells in a 48-well microchemotaxis chamber was determined. Nonstimulated (control) migration was remarkably constant (mean +/- SD, 96 +/- 14) from plate to plate, thus allowing the indexing of relative migration of stimulated cells to that of nonstimulated cells in the control wells of that plate. Based on the relative migrations observed in response to each of the substances evaluated, those proving to be stimulatory of migration were placed in rank order by potency. The growth factors epidermal growth factor, transforming growth factor-alpha, and basic fibroblast growth factor (followed by pentosan polysulfate, plasmin, fibronectin, fibrinogen, granulocyte-macrophage colony stimulating factor heparin, adenosine, and MgSO4) were the most potent. Only the platelet factors platelet-derived growth factor-BB and platelet activating factor proved inhibitory of migration. Combining fibrinogen with other chemoattractants produced either stimulation or inhibition in comparison to the migration observed with fibrinogen alone, suggesting that more than one signal transduction mechanism was, in all likelihood, invoked by the various agents. This assay will allow the rapid screening and rank ordering of additional putative chemoattractants, will facilitate the study of the biochemical mechanisms involved in endothelial cell migration, and will permit the evaluation of pharmacologic agents capable of modulating stimulated or unstimulated migration.

Risk factors for stroke in patients undergoing coronary artery bypass grafting

Stroke is a significant cause of morbidity and mortality following coronary artery bypass grafting (CABG). Over a 30-month period, 245 consecutive patients undergoing elective CABG were prospectively examined to determine which risk factors might predispose to stroke following surgery. The risk factors evaluated included hypertension, diabetes, hypercholesterolemia, hypertriglyceridemia, smoking, atrial fibrillation, a history of cerebrovascular accident or transient ischemic attack, carotid artery stenosis > 60% documented by duplex scanning, severe atherosclerosis of the ascending aorta, and the presence of ventricular thrombus. Postoperative stroke occurred in five of the 245 patients (2%), four evident immediately on awakening and one on day 7 after surgery. The probable causes of the immediate strokes were atheroembolism in three patients and severe ipsilateral carotid stenosis in one. Hypertensive hemorrhage was responsible for the one case of delayed stroke. In this study, carotid artery stenosis did not presage stroke following CABG, but ventricular thrombus was highly predictive of stroke after surgery.

Hepatic ischemia, caused by celiac axis compression, complicating pancreaticoduodenectomy

OBJECTIVE

In the course of pancreaticoduodenectomy, profound hepatic ischemia developed in two patients (one with ampullary carcinoma, the other with chronic pancreatitis). This article addresses the diagnosis and correction of the celiac axis compression responsible in this complication.

SUMMARY BACKGROUND DATA

Since hepatic ischemia appeared immediately after division of the gastroduodenal--pancreaticoduodenal arcade, which provides mesenteric to celiac collateral circulation, celiac axis narrowing or occlusion was suspected. Previous reports have indicated that celiac axis disease may be present in about 10% of such patients.

METHODS

Doppler flow studies, and in the second patient, intraoperative angiography were performed. The celiac axis was exposed and mobilized in both.

RESULTS

Initially, no flow could be detected in the celiac axis. Dense fibrous tissue was found encasing it. Division of the entrapping tissue restored flow to the upper abdominal viscera.

CONCLUSIONS

The anatomic deformation of the celiac axis predisposing to this complication is detectable on the lateral projection of a preoperative celiac angiogram. If, however, an angiogram has not been done, an initial test occlusion of the gastroduodenal artery before its division permits anticipation of the complication, correction of the celiac impingement, and hence, avoidance of hepatic ischemia.

Thrombectomy and isolated limb perfusion with urokinase in the treatment of phlegmasia cerulea dolens

Phlegmasia cerulea dolens is a rare form of deep vein thrombosis. A patient with recurrent episodes of such thrombosis caused by protein C deficiency who developed phlegmasia cerulea dolens is reported. Limb perfusion with urokinase successfully restored venous outflow after unsuccessful attempts at thrombectomy.

Effect of surgical manipulation of polytetrafluoroethylene grafts on microstructural properties and healing characteristics

The effects on graft healing of alterations in the microstructure of polytetrafluoroethylene (PTFE) grafts induced by surgical instruments have not been fully elucidated. This study evaluates changes in the structural and physical properties of PTFE grafts resulting from the intentional application of commonly used surgical instruments and the influence of these changes on cellular ingrowth. The extent of cellular ingrowth into intact (10, 30, and 60 microns unreinforced and 30 microns reinforced [R]) and structurally compromised PTFE grafts (30 reinforced and 60 microns nonreinforced) implanted subcutaneously in Sprague-Dawley (n = 14) rats was evaluated at 7 and 21 days. The thrombogenicity of 10-, 30-, 60-, and 80-microns intact graft segments was determined gravimetrically after suspension in the internal jugular vein of dogs for 90 minutes. Cellular ingrowth consisting of fibroblasts, macrophages, and microvessels was directly related to porosity and was most extensive in 60-microns uncompromised graft segments, being 7-, 17-, and 20-fold greater than was observed in 60- and 30R-microns compromised grafts and undamaged 10-microns grafts, respectively. There was a direct relationship between porosity and thrombogenicity of intact graft segments suspended in the jugular vein. The amount of thrombus adherent to 80-microns graft segments was eightfold greater compared with 10-microns grafts. Manipulation of PTFE with surgical instruments significantly impairs healing and may be a possible etiologic factor in the poor long-term performance of these grafts.

Peripheral vascular disease in heart transplant recipients

The improved longevity of heart transplant recipients demands heightened awareness of the long-term complications of the procedure. Between 1979 and 1990, 232 patients received 241 heart transplants at our institution. Accelerated coronary atherosclerosis occurred in 45 (19%) of the 232 patients, typically appearing within 2 years of transplantation, whereas peripheral vascular disease (PVD) appeared in 23 (10%) of the 232 patients, usually within 3 years of transplantation. In the patients with PVD, 13 had occlusive disease, nine had aneurysms, and one patient suffered a vertebral artery dissection. Accelerated coronary atherosclerosis afflicted 12 (52%) of the 23 patients affected by PVD (p < 0.05) and preceded the development of PVD in all 12. Logistic regression analysis revealed risk factors predictive of the development of PVD after transplantation to be a pretransplant history of ischemic cardiomyopathy and posttransplant hypertension and hypertriglyceridemia (p < 0.05), with the presence of more than one risk factor increasing the probability of development of PVD. Those patients thus identified as at risk should be closely monitored for the development of PVD. Aggressive medical management of hypertension and hyperlipidemia in this subpopulation may forestall or prevent the development of peripheral vascular disease after heart transplantation.

Contrast-induced nephrotoxicity: the effects of vasodilator therapy

The increasingly frequent use of contrast-enhanced imaging for diagnosis or intervention in patients with peripheral vascular disease has generated concern about the incidence and avoidance of contrast-induced nephrotoxicity (CIN). In this prospective study, we sought to identify those patients at greater risk of developing CIN and to evaluate the efficacy of vasodilator therapy with dopamine in limiting this complication. Baseline serum creatinine (Cr) concentrations were obtained on admission and daily for up to 72 hr after angiography in 222 patients undergoing 232 angiographic procedures. The preangiographic treatment was varied at 2-month intervals for 1 year. All patients received an intravenous infusion of 5% dextrose and 0.45% normal saline at a rate of 75 to 125 ml/hr. During the first interval patients received 12.5 g of 25% mannitol immediately prior to their contrast load, in addition to intravenous fluids. During the next 2-month period the patients were given renal dose dopamine intravenously (3 micrograms/kg/min) commencing the evening before angiography and continued to the next morning. During the latter half of the study the treatment regimens were modified so that the use of mannitol was restricted to patients with diabetes mellitus and dopamine to patients with serum creatinine concentrations of > or = 2 mg/dl. Postangiographic elevation in Cr occurred in 2, 10.4, and 62% of studies in patients with baseline creatinine levels of < or = 1.2 mg/dl, 1.3 to 1.9 mg/dl, and > or = 2.0 mg/dl, respectively. None of the patients receiving dopamine experienced an elevation in creatinine. There was no statistical correlation between age, diabetes, or medication with calcium channel blockers and CIN.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation of ophthalmic findings with carotid artery stenosis

Patients presenting with symptoms suggestive of amaurosis fugax, or with findings of Hollenhorst plaques on fundoscopy are frequently referred for duplex evaluation to detect possible carotid artery disease. To better determine the reliability of monocular visual loss and the presence of Hollenhorst plaques for predicting the presence or significance of carotid artery stenosis, we prospectively studied 66 patients with these ocular signs and symptoms. After evaluation, the patients were categorized as follows: 34 of 66 (52%) patients had amaurosis fugax, 23 (35%) had asymptomatic Hollenhorst plaques, 7 (11%) had retinal artery occlusion, and 2 (3%) had venous stasis retinopathy. All patients were evaluated ophthalmologically, with carotid duplex scanning and spectral analysis. A stenosis of greater than 60% was regarded as significant. The presence of risk factors including hypertension, diabetes, a history of CVA or TIA's, tobacco use and hyperlipidemia was recorded. There were no statistically significant differences (p greater than 0.05) in the incidence of atherosclerotic risk factors between the four groups. Patients with amaurosis fugax were more likely to have a significant carotid artery stenosis than those with asymptomatic Hollenhorst plaques or retinal artery occlusion (53% vs 9% vs 0% respectively) (p less than 0.006). We conclude that routine carotid duplex scanning is indicated in all patients with amaurosis fugax in view of the frequent association with significant carotid stenosis (53%). However, the presence of Hollenhorst plaques in the absence of visual symptoms appears not to have a significant association with carotid disease and may not necessarily require routine screening unless other risk factors for carotid stenosis are present.(ABSTRACT TRUNCATED AT 250 WORDS)

Atherosclerotic aneurysms of the axillary artery. A report of two cases and a review of the literature

Atherosclerotic axillary artery aneurysms are rare. We report two cases of this entity and review the literature with respect to clinical presentation, diagnosis, operative management, and long-term outcome of these lesions.

Improved sterile technique diminishes the incidence of positive line cultures in cardiovascular patients

In order to determine the incidence of positive line cultures, especially as affected by differing protocols for line insertion, cultures were obtained from lines in residence for up to 4 days from cardiac patients (who received Cefuroxime) and vascular patients (who received Cefazolin) as prophylaxis perioperatively. Positive cultures were obtained from 95 (19%) of 496 lines in cardiac patients and 83 (31%) of 261 lines in vascular patients. There was a linear relationship between duration of line residence and the incidence of positive line cultures, increasing from 14% on Day 1 to 33% on Day 4. The use of full sterile technique at the time of insertion halved the incidence of subsequent positive line cultures. Four of the 403 (1%) patients each had a single episode of postoperative line sepsis. Another four patients developed wound infections with the same organisms as cultured from their lines. One patient has had a vascular graft infection with the same organism cultured as was isolated from a Swan-Ganz line 1 year previously. These data suggest that monitoring lines should be inserted using full sterile technique and removed as soon as the patient is hemodynamically stable.

Outcome of intraarterial urokinase for acute vascular occlusion

Intraarterial urokinase (IAUK) was administered to 33 patients on 40 occasions for the treatment of acute extremity ischemia and long-term patency was assessed. Lysis was successful in 39 of the 40 cases (95%). Occlusive thrombus was cleared in 12 of 13 patients with native artery occlusion (7 complete, 5 partial), 8 of 9 with autologous vein grafts (5 complete, 3 partial), and in all 18 patients with synthetic grafts (17 complete, 1 partial). The primary cumulative patency following successful IAUK was 100% for native arteries and 47% for synthetic grafts at 12 months, and 23% for autologous grafts at 9 months. The difference in rethrombosis rate between autologous vein (67%) and native artery (0%) was significant (p = 0.02) as was the difference between infrainguinal prosthetic grafts (63%) and native artery (p = 0.025). IAUK is most effective for the treatment of native artery occlusion, but is significantly less effective for thrombosed infrainguinal autologous vein or synthetic grafts due to the likelihood of reocclusion, despite the high immediate success rate. For autologous vein grafts, lysis is frequently incomplete and patency rapidly deteriorates regardless of adjunctive therapy to relieve the underlying obstruction.

Gallstone pancreatitis. Choosing and timing treatment

Patients with gallstone pancreatitis are often seen initially by primary care physicians. Prompt diagnosis and timely intervention are crucial in reducing morbidity and mortality. Initial management should include supportive medical care and surgical consultation. The timing of surgery is then dictated by serum enzyme levels and liver function test results as well as by the patient's condition. The role of endoscopic intervention is currently evolving. Whether surgery or endoscopic sphincterotomy is preferable as primary therapy for gallstone pancreatitis remains unresolved. However, sphincterotomy with stone extraction is a viable option in selected cases, especially in patients who have severe gallstone pancreatitis.

The acutely affected abdomen in paraplegic spinal cord injury patients

The records of 145 paraplegic or quadriplegic patients were reviewed to identify those factors useful in the correct diagnosis of the acute abdomen in this population. Twenty-one patients had 22 episodes of acute or subacute abdominal problems. Presenting complaints, physical findings, and laboratory results were useful in various ways. However appropriate radiographic studies led to the correct diagnosis in 77% of patients. Although paraplegic and quadriplegic patients are predisposed to a distinct constellation of medical problems, including urinary tract infection and calculi, they also may present with other abdominal conditions that cause significant morbidity and mortality if not promptly recognized.