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PubMed2006

[Comparative analysis of macular hole surgery followed by internal limiting membrane removal with and without indocyanine green staining].

PURPOSE: To describe comparatively the outcomes of macular hole surgery followed by internal limiting membrane removal with and without indocyanine green staining. METHODS: We evaluated 142 consecutive macular hole surgeries with internal limiting membrane removal performed in the period from January 2001 to March 2004. These were divided into two groups, based on the use or not of indocyanine green staining. RESULTS: Both studied groups were similar concerning the patients' profile and preoperative stage of the macular holes. Mean preoperative visual acuity was 0.12+/-0.15 in the group with indocyanine green staining and 0.18+/-0.18 in the group without internal limiting membrane staining (p=0.02). Mean postoperative visual acuity was 0.27+/-0.27 in the group with internal limiting membrane staining and 0.43+/-0.25 in the group without internal limiting membrane staining (p=0.0002). We observed improvement of visual acuity in 63% of cases in the group in which internal limiting membrane staining was performed and in 80.3% of cases in the group without internal limiting membrane staining. Macular hole closure rates were 76.5% in the group treated with internal limiting membrane staining and 95.1% in the group treated without internal limiting membrane staining. CONCLUSIONS: Macular hole surgeries followed by internal limiting membrane removal without use of staining have better visual and anatomic results when compared to macular hole surgeries followed by internal limiting membrane removal guided by indocyanine green staining. We recommend caution in using indocyanine green staining in macular hole surgeries due to its possible toxic effect.

Adult↗
PubMed1991

Ligand induced internalization of epidermal growth factor receptors by A431 cells decreases at high cell densities in culture.

Internalization of epidermal growth factor (EGF) receptors by human A431 epidermoid carcinoma cells was studied at various culture densities. The extent of EGF receptor internalization was measured by quantitation of internalized 125I-EGF during incubation at 37 degrees C for 30 min. When cell culture density was below 1 x 10(5) cells/cm2 receptor internalization was active; 30-40% excess moles of ligand over the moles of surface EGF receptors were internalized during this period. However, when culture density increased to above 1.5 x 10(5) cells/cm2 receptor internalization became less extensive, as only 30-50% of ligand bound to the cell surface underwent internalization during 30 min incubation. In parallel with this reduction in receptor internalization, the degradation rate of 35S-methionine labeled EGF receptors was reduced at a high culture density. In contrast with this regulation of receptor internalization, the affinity of EGF receptors for the ligand increased as culture density increased. The extent of EGF-dependent receptor phosphorylation was found to be constant at all culture densities tested. Thus, the observed low level of receptor internalization at high culture densities was not attributable to lower responsiveness of receptors to EGF. These data suggest the presence of an as yet unidentified cell density-dependent mechanism for regulating receptor internalization in cultured A431 cells.

Adenosine Triphosphate↗
PubMed1989

Evaluating interns' performance using simulated patients in a casualty department.

An observational study examined the care that was provided by 61 interns for three simulated (standardized) patients in a casualty department within a large teaching hospital. The consultations were recorded on videotape and were scored by reference to explicit criteria that were set by an expert panel. The criteria described standards of clinical competence, communication skills and preventive care for each of the three cases. An additional list of the general opportunities for preventive advice that were suggested by the patients' case histories also was compared with the interns' actual behaviour. Clinical competence was not demonstrated uniformly across the three cases. The problem of urinary-tract infection was managed best; 19% of the interns complied with all criteria, and 93% of the interns complied with 75% of the criteria. For tension headache, only 3% of the interns complied with all the criteria but 67% of interns complied with 75% of the criteria. In the case of bronchitis, only 3% of interns complied with all the criteria but 58% of interns met 75% of the criteria. The quality of preventive care also varied from case to case, being best for the patient with bronchitis and worst for the patient with tension headache. Over all, only three of the 13 criteria were met by more than half the interns. The communication-skills criteria identified three behaviours which the interns were most likely to omit: the interns summarized the patients' problems in only 73 of the 173 consultations; they explained the aetiology of the problems in only 127 of the 173 consultations; and they ensured that the patients understood their plan of management in only 21 of the 173 consultations.

Adult↗
PubMed2000

Long-term angiographic evaluation of free internal thoracic artery grafting for myocardial revascularization.

Between 1990 and 1998, 41 patients underwent free internal thoracic artery grafting for coronary artery bypass. To investigate usefulness of free internal thoracic artery grafting, we compared the postoperative graft patency of free internal thoracic artery grafts with that of in situ internal thoracic artery grafts, and compared the long-term results such as actual survival and cardiac-event free rate in patients receiving free internal thoracic artery grafts with those results in patients receiving in situ internal thoracic artery grafts. Postoperative changes in luminal diameter of free internal thoracic artery grafts were calculated as the difference between the first and secondary angiographic evaluation in 17 patients who were followed-up for more than 5 years. The early postoperative graft patency rate of free internal thoracic artery was 95.2%. All these early patent grafts remained patent at the time of the late study. At 9 years post-surgery, patients who received free internal thoracic artery grafts had a survival rate of 100% and a cardiac event-free rate of 77.5%; the luminal diameter enlargement was 0.57 mm, and the mean matching rate increased 27.8%. We conclude that the free internal thoracic artery provides long-term results comparable with those of in situ internal thoracic artery.

Aged↗
PubMed1992

Detrimental sequelae on the wall of the internal mammary artery caused by hydrostatic dilation with diluted papaverine solution.

We studied the effect of hydrostatic dilation of the internal mammary artery used for coronary revascularization in 10 patients (aged 45 to 79 years, median 63 years). Diluted papaverine solution was injected in the lumen of distal segments of the internal mammary artery, the musculophrenic artery, or the superior epigastric artery that had been obtained at operation; injection was followed by hydrostatic dilation not exceeding a sheer force of 50 gm. In 12 control patients (aged 42 to 76 years, median 64 years) in whom the internal mammary artery had also been harvested for elective myocardial revascularization, similar arterial segments were wrapped in sponges soaked in papaverine solution of the same dilution. In the nondilated group the median (with interquartile range) number of fenestrations in the internal elastic lamina increased from the elastic (21, 7) to the elastomuscular (41, 11) and muscular segments (89, 12) (elastic-elastomuscular: p = 0.006; elastic-muscular: p = 0.006; elastomuscular-muscular: p = 0.003) (Wilcoxon signed-rank test). In none of the three histologic segments were full-thickness disruptions of the intima and disruptions of the internal elastic lamina seen. Similarly, in the dilated group the number of fenestrations in the internal elastic lamina increased from the elastic (25, 18) to the elastomuscular (43, 9) and muscular (100, 13) segments (p values 0.01, 0.01, and 0.006, respectively). In addition, in 20% of the elastic sections, in 17% of the elastomuscular sections, and in 35% of the muscular sections of the dilated group, disruptions of the intima and internal elastic lamina were seen. Comparison of the number of fenestrations in internal elastic lamina in the three histologic segments between the nondilated and dilated groups revealed a significantly greater value in the muscular segments of the latter group (p = 0.01) (Mann-Whitney U test). We concluded that (1) hydrostatic dilation of the internal mammary, musculophrenic, and superior epigastric arteries may have detrimental effects on the histologic characteristics of the intima and the internal elastic lamina and (2) the number of fenestrations in the internal elastic lamina of these arteries is related to the presence or absence of elastic lamellae in the media.

Aged↗
PubMed1992

Basic fibroblast growth factor is internalized through both receptor-mediated and heparan sulfate-mediated mechanisms.

Basic fibroblast growth factor (bFGF) was internalized at a rapid rate by Chinese hamster ovary (CHO) cells that do not express significant numbers of high affinity receptors for bFGF as well as CHO cells that have been transfected with cDNA encoding FGF receptor-1 or FGF receptor-2. Internalization of bFGF was completely blocked by the addition of 10 micrograms/ml heparin in the parental CHO cells but only partially inhibited in cells expressing transfected FGF receptors. Bovine aortic endothelial cells also exhibit heparin-sensitive and heparin-resistant internalization of bFGF. The internalization of bFGF through the heparin-resistant pathway in CHO cells was efficiently competed by addition of unlabeled bFGF, was proportional to the number of receptors expressed, and approached saturation, suggesting that the heparin-resistant internalization was due to high affinity receptors. Internalization of bFGF through the heparin-sensitive pathway was not efficiently competed by unlabeled bFGF and did not approach saturation at concentrations of bFGF up to 50 ng/ml, properties similar to the interaction of bFGF with low affinity heparan sulfate binding sites on the cell surface. Internalization of bFGF in CHO cells not expressing FGF receptors was inhibited by heparin, heparan sulfate, and dermatan sulfate, the same glycosaminoglycans that block binding to cell-surface heparin sulfates. Internalization of bFGF in the parental CHO cells was inhibited at the same concentrations of heparin that block binding to cell-surface heparan sulfates. Finally, inhibition of the sulfation of CHO cell heparan sulfates by the addition of chlorate or digestion of CHO cell heparan sulfates with heparinase inhibited bFGF internalization in the parental CHO cells. These results demonstrate that bFGF can be internalized through a direct interaction with cell-surface heparan sulfates. Thus, there are two pathways for internalization of bFGF: high affinity receptor-mediated and heparan sulfate-mediated.

Animals↗
PubMed2005

[Improvement of the recruitment of surgery interns derived from the Epreuves Nationales Classantes (National-Ranking Exam): practical solution applied to urology].

OBJECTIVES: To analyse the value of an urology initiation session proposed to young interns to improve recruitment of the discipline since the introduction of the new National-Ranking Exam (NRE). MATERIALS AND METHODS: In October 2004, the 77 interns appointed to surgery in Paris on the basis of the ENC participated in a one-day urology initiation session organized by the AFUF, at the AP-HP School of Surgery. All interns were given a questionnaire at the beginning of the session to record the following data: age, gender, teaching hospital, a student attachment in urology and desired specialization as a function of the surgical training programmes proposed by the ENC. Items concerning the desired specialization were resubmitted to the interns at the end of the session. RESULTS: Population. 77 interns, 48 females (62.3%) and 29 males (37.7%) with a mean age of 25.2 +/- 5 years (range: 23-31). 55 interns had trained at a Parisian teaching hospital (67%) and 22 (28.6%) had trained at a provincial teaching hospital. 16 interns (20.8%) had completed at least one urology attachment during their medical training. Desired specialization. Orthopaedics was the discipline most frequently cited (n = 20; 26%). Urology was chosen by 8 interns (10.40%), who had all completed an urology attachment during their medical training. At the end of the urology initiation session, another 8 interns expressed the desire to specialize in urology. Of the 16 potential urology interns, 9 (56.2%) confirmed that their decision was final. CONCLUSION: Urology occupies a special place and remains a popular surgical speciality among students. Organization of practical sessions constitutes a solution to inform, create an emulation and motivate surgery interns to choose urology.

Adult↗
PubMed1990

Quantitative analysis of the endocytic system involved in hormone-induced receptor internalization.

We have developed a quantitative method to evaluate the interaction between cell surface receptors and the endocytic apparatus. This method exploits occupancy-dependent changes in internalization rates that occur in cells expressing high numbers of receptors. We found that constitutive internalization of the transferrin receptor behaves as a simple, first order process that is unaltered by ligand. Internalization of the epidermal growth factor (EGF) receptor, however, behaves as a saturable, second order process that is induced by receptor occupancy. Internalization of EGF receptors occurs through at least two distinct pathways: a low capacity pathway that has a relatively high affinity for occupied receptors, and a low affinity pathway that has a much higher capacity. The high affinity pathway was observed in all cells having receptors with intrinsic tyrosine kinase activity. Mutant EGF receptors lacking kinase activity could not utilize the high affinity pathway and were internalized only through the low affinity one. Mutated receptors with decreased affinity for kinase substrates were also internalized at decreased rates through the high affinity, inducible pathway. In the case of vitellogenin receptors in Xenopus oocytes, occupied receptors competed more efficiently for internalization than empty ones. Insulin increased the endocytic capacity of oocytes for vitellogenin receptors. Similarly, serum increased the capacity of the inducible pathway for EGF receptors in mammalian cells. These data are consistent with a model of internalization in which occupied receptors bind to specific cellular components that mediate rapid internalization. Ligand-induced internalization results from an increase in the affinity of occupied receptors for the endocytic apparatus. Hormones can also indirectly regulate endocytosis by increasing the number of coated pits or their rate of internalization. The ability to dissect receptor-specific effects from cell-specific ones should be very useful in investigating the molecular mechanisms of receptor mediated endocytosis.

Animals↗
PubMed1989

Ligand-induced desensitization of 125I-epidermal growth factor internalization.

The internalization of 125I-epidermal growth factor (EGF) by A431 cells was investigated. Control cells were able to internalize over 80% of receptor-bound 125I-EGF. By contrast, cells treated with EGF before incubation with 125I-EGF internalized only 50% of the surface-bound radioligand. The ligand-induced decrease in 125I-EGF internalization showed a dose response to EGF with half-maximal effect occurring at 3 nM. The alteration in the extent of 125I-EGF internalization did not require extended treatment with high concentrations of the hormone. When the internalization of picomolar versus nanomolar concentrations of EGF were compared, the lower concentrations of 125I-EGF were more completely internalized than the higher concentrations of radioligand. These data are consistent with the hypothesis that occupation of the EGF receptor by hormone rapidly leads to the activation of cellular processes which effectively desensitize the system to further ligand-induced internalization. The decrease in the extent of ligand internalization occurred in cells in which the protein kinase C (Ca2+/phospholipid-dependent enzyme) activity had been down-regulated by prolonged treatment with 12-O-tetradecanoyl-phorbol-13-acetate implying that the desensitization process is independent of protein kinase C. However, the effects of EGF on the extent of hormone internalization could be mimicked by the addition of A23187 and could be prevented by pretreatment of the cells with calmodulin antagonists suggesting the possibility that Ca2+-calmodulin is involved in the regulation of EGF receptor internalization in A431 cells.

Animals↗
PubMed1996

Rapid agonist-induced internalization of the 5-hydroxytryptamine2A receptor occurs via the endosome pathway in vitro.

The mechanism by which agonists induce 5-hydroxytryptamine2A (5-HT2A) receptor internalization was investigated in a clonal cell line stably transfected with the 5-HT2A receptor cDNA. Confocal laser microscopy of immunolabeled 5-HT2A receptors in control (untreated) cells demonstrated that most of the immunoreactivity was associated with the cell surface. After quipazine administration, a significant increase in intracellular immunofluorescence was measured. Time course studies demonstrated rapid agonist-dependent internalization of 5-HT2A receptors, with significant internalization occurring as early as 5 min after agonist administration at 37 degrees. In GF-62 cells, agonist-induced internalization was blocked by preincubation with the 5-HT2A receptor antagonist ketanserin. Internalization was also temperature sensitive because agonist-induced internalization did not occur at 4 degrees. Dual-label experiments disclosed that 5-HT2A and transferrin receptors were internalized via the same endocytotic vesicles. These results suggest that 5-HT2A receptors and transferrin receptors are internalized via the endosomal pathway in GF-62 cells. Although 5-HT2A receptors were internalized, down-regulation, or loss of radioligand binding sites, did not occur. Our results demonstrate that agonists rapidly induce 5-HT2A receptor internalization via the endosomal pathway and that internalization can be dissociated from down-regulation.

3T3 Cells↗
PubMed1998

CD14-dependent internalization of bacterial lipopolysaccharide (LPS) is strongly influenced by LPS aggregation but not by cellular responses to LPS.

We analyzed the impact of ligand aggregation and LPS-induced signaling on CD14-dependent LPS internalization kinetics in human monocytic THP-1 cells and murine macrophages. Using two independent methods, we found that the initial rate and extent of LPS internalization increased with LPS aggregate size. In the presence of LPS binding protein (LBP), large LPS aggregates were internalized extremely rapidly (70% of the cell-associated LPS was internalized in 1 min). Smaller LPS aggregates were internalized more slowly than the larger aggregates, and LPS monomers, complexed with soluble CD14 in the absence of LBP, were internalized very slowly after binding to membrane CD14 (5% of the cell-associated LPS was internalized in 1 min). In contrast, the initial aggregation state had little or no effect on the stimulatory potency of the LPS. Previous studies suggest that LPS-induced signal responses may influence the intracellular traffic and processing of LPS. We found that elicited peritoneal macrophages from LPS-responsive (C3H/HeN) and LPS-hyporesponsive (C3H/HeJ) mice internalized LPS with similar kinetics. In addition, pre-exposure of THP-1 cells to LPS had no effect on their ability to internalize subsequently added LPS, and pre-exposure of the cells to the LPS-specific inhibitor, LA-14-PP, inhibited stimulation of the cells without inhibiting LPS internalization. In these cells, LPS is thus internalized by a constitutive cellular mechanism(s) with kinetics that depend importantly upon the physical state in which the LPS is presented to the cell.

Animals↗
PubMed2003

In situ retrocaval skeletonized right internal thoracic artery anastomosed to the circumflex system via transverse sinus: technical aspects and postoperative outcome.

BACKGROUND: The aim of this study was to investigate whether, by using the in situ right internal thoracic artery via the transverse sinus (eventually retrocaval), both the proximal and distal major branches of the circumflex system could be grafted and to evaluate the early and late outcome in these patients. METHODS: Between January 1997 and March 2002, 452 consecutive patients underwent grafting of the circumflex system with the in situ skeletonized right internal thoracic artery routed via the transverse sinus. The mean age was 62.4 +/- 10.3 years. A mean of 2.2 +/- 0.3 arterial grafts per patient were used, and 271 (60%) patients underwent total arterial myocardial revascularization. At 3 months after surgery, 86 patients (right Y or T graft) underwent echo color Doppler imaging before and after an adenosine provocative test. The mean follow-up was 27 +/- 8 months. RESULTS: The success rate of skeletonized right internal thoracic artery grafting to the circumflex system branch was 100%. There were 15 (3.4%) hospital deaths. In 116 patients who underwent postoperative angiography, the total patency rates of the right and left internal thoracic arteries were 94% and 96.6%, respectively. Strong predictors for nonfunctional internal thoracic artery grafts were a small internal thoracic artery caliber (P <.001), recipient coronary artery diameter less than 1.5 mm (P =.012), stenotic lesions of less than 60% (P =.016), and diffuse stenotic lesions (P =.015) of the recipient coronary artery. In 86 patients who underwent postoperative echo color Doppler imaging, the flow reserves at the main stem of the left and right internal thoracic arteries were 2.24 +/- 0.5 and 2.48 +/- 0.6, respectively. Cumulative actuarial survival at 3 years was 96.3%, and event-free cumulative survival was 93%. The Cox model revealed a left ventricular ejection fraction of less than 35% (P =.016), age greater than 70 years (P =.025), New York Heart Association grade greater than III (P =.0019), nontotal arterial myocardial revascularization (P =.002), and the preoperative presence of more than 1 ischemic area (P <.001) as strong predictors for poor overall cumulative event-free survival. CONCLUSIONS: The skeletonized right internal thoracic artery, placed via the transverse sinus and eventually retrocaval, can reach most branches of the circumflex system and is associated with an excellent patency rate. The predictors for poor overall event-free survival seem to be similar to those of the general population undergoing conventional coronary artery bypass grafting. Use of bilateral internal thoracic arteries and in situ right internal thoracic artery grafting via the transverse sinus offers the possibility of various configuration constructions, making possible total arterial myocardial revascularization with a minimum number of arterial conduits.

Adult↗
PubMed1996

Prospective evaluation of new duplex criteria to identify 70% internal carotid artery stenosis.

PURPOSE: Large multicenter trials (North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial) have documented the benefits of carotid endarterectomy for treating symptomatic patients with >or=70% stenosis of the internal carotid artery. Although color-flow duplex scanning has become the preferred method for noninvasive assessment of internal carotid artery disease, no criteria have been generally accepted to identify this subset of patients. We previously reported a retrospective series to establish such criteria. This study details our results when these criteria were applied prospectively. METHODS: Carotid color-flow duplex scans were compared with arteriograms in 457 patients who underwent both studies. Criteria for >or=70% internal carotid artery stenosis were peak systolic velocity >130 cm/sec and end-diastolic velocity >100 cm/sec. Internal carotid arteries with peak systolic velocity <40 cm/sec in which only a trickle of flow could be detected were classified as preocclusive lesions (95% to 99% stenosis). Arteriographic stenosis was determined by comparing the diameter of the internal carotid artery at the site of maximal stenosis to the diameter of the normal distal internal carotid artery. RESULTS: Internal carotid artery stenosis of >or=70% was detected with a sensitivity of 87%, specificity of 97% positive predictive value of 89%, negative predictive value of 96%, and overall accuracy of 95%. Eighty-seven percent of 70% to 99% stenoses were correctly identified. False-positive errors (n=10) were attributed to contralateral internal carotid artery occlusion or high-grade (>90%) stenosis (n=5) and to interpreter error (n=1); no explanation was apparent in the other four. Eleven of 12 false-negative examinations occurred in patients with 70% to 80% internal carotid artery stenosis. CONCLUSIONS: In our laboratories, prospective application of the above velocity criteria identified internal carotid artery stenosis of >or=70% with a reasonably high degree of accuracy. Errors occurred when stenoses were borderline and in patients with severe contralateral disease. With suitably modified velocity criteria, color-flow duplex scanning remains the most reliable noninvasive method for identifying symptomatic patients who are candidates for carotid endarterectomy.

Angiography↗
PubMed2004

International content of high-ranking nursing journals in the year 2000.

PURPOSE: To evaluate the extent of an international perspective in publication in nursing journals. DESIGN: Characteristics of 2,581 articles, authors of articles, and journals (editorial purpose and editorial team) of 42 high-ranking nursing journals for the year 2000 were analyzed. METHODS: The characteristics were assessed using seven operational definitions of "international." FINDINGS: Major findings were: (a) 747 (28.9%) articles were identified as international, of which (b) 705 (94.3%) were placed in the scholarly or empirical categories; (c) more articles were categorized as empirical in the international articles; more articles were categorized as scholarly among the noninternational articles; (d) 763 (79.3%) articles met an international definition based on author characteristics; and (e) 20 (47.6%) journals had international editorial teams. CONCLUSIONS: Nearly 30% of articles had international content. Articles with international content were more frequently databased than were noninternational articles. The study provides a baseline indication of the extent of international perspectives in published articles in nursing journals. The extent to which these international articles make substantial contributions to knowledge has yet to be discovered.

Authorship↗
PubMed2006

The effects of on-duty napping on intern sleep time and fatigue.

BACKGROUND: Naps during extended work shifts are effective in reducing fatigue in other industries, but the use of a nap as a countermeasure to prevent fatigue in residents is uncertain. OBJECTIVE: To assess the effects of a call-night nap on resident sleep and fatigue. DESIGN: 1-year, within-participant, paired trial with crossover at midmonth. SETTING: Academic teaching hospital. PARTICIPANTS: 38 of 40 internal medicine interns. MEASUREMENTS: Sleep was measured by using wristwatch actigraphy. By using the experience sampling method on a personal digital assistant, random alerts prompted interns to rate fatigue on the 7-point Stanford Sleepiness Scale (7 is most tired). Hospital paging logs and structured interviews provided information on use of coverage. INTERVENTION: For 2 weeks of every month, interns were assigned to the nap schedule, which provided coverage to on-duty interns from midnight to 7:00 a.m. so that they could finish their work and take a nap. The other 2 weeks of the month constituted a standard schedule. RESULTS: Interns received 41 more minutes of sleep while on call with the nap schedule (185 minutes vs. 144 minutes; P < 0.001). When interns with the nap schedule used coverage, they received 68 more minutes of sleep (210 minutes vs. 142 minutes; P < 0.001). Despite these small increases in sleep, interns reported less overall fatigue while on the nap schedule than while on the standard schedule (1.74 vs. 2.26; P = 0.017). Postcall fatigue with the nap schedule was lower by nearly 1 point (2.23 vs 3.16; P = 0.036), which is almost equivalent to the difference between on-call and postcall fatigue with the standard schedule (2.06 vs. 3.16). However, use of coverage by interns on the nap schedule was impaired by their desire to care for their patients and concerns about discontinuity of care. LIMITATIONS: This was a single-institution study that did not have the power to examine outcomes related to intern or patient well-being. CONCLUSIONS: Coverage to allow a nap during an extended duty-hour shift can increase sleep and decrease fatigue for residents.

Continuity of Patient Care↗
PubMed2004

Preoperative semi-selective left internal mammary artery angiography: easy, safe, necessary and worthy.

AIM: The left internal mammary artery is the graft of choice for coronary artery bypass surgery. The necessity for preoperative internal mammary artery angiography is still controversial. We designed a prospective left internal mammary angiography for evaluating the risk of stenosis in the left internal mammary and subclavian artery, and the risk and the necessity for pre-operative internal mammary artery angiography. METHODS: Eighty-six patients were included in a prospective study for semi-selective left internal mammary artery angiography during cardiac catheterization via the left radial or femoral approach. Stenosis of the left internal mammary and proximal left subclavian arteries was calculated with DCA; Chi2 analysis was used for analyzing the correlation between the risk factors and arterial stenosis. RESULTS: One patient (1.2%) showed left internal mammary artery stenosis and 5 (5.8%) showed proximal left subclavian artery stenosis. No complications were found in all cases. The only significant factor affecting left subclavian or internal mammary artery stenosis was the female sex. All patients tolerated the procedure well. CONCLUSION: Semi-selective left internal mammary artery angiography is a safe and easy procedure that should be performed routinely for patients with CAD prior to coronary artery bypass surgery.

Aged↗
PubMed1986

Flow capacity of the canine internal mammary artery.

The internal mammary artery has excellent long-term patency when used as a conduit for coronary artery bypass, and clinical and experimental studies have shown that blood flow through an internal mammary artery graft is satisfactory for most coronary artery branches. Multiple distal anastomoses from a single internal mammary artery, either with sequential anastomoses or with a Y-graft, might require additional blood flow through the vessel, and there has been concern that the flow capacity of the internal mammary artery is insufficient with these techniques. To better define the immediate postoperative flow capacity and pattern of the internal mammary artery, we performed experiments in seven dogs in which the left internal mammary artery was anastomosed to the circumflex coronary artery. In situ, blood flow in the internal mammary artery was 27 ml/min. Blood flow was 63 ml/min in the circumflex coronary artery and 42 ml/min in the left anterior descending coronary artery. After anastomosis of the left internal mammary artery to the circumflex coronary artery, the left main coronary artery was ligated; flow through the bypass graft increased to 92 ml/min, and systemic hemodynamics remained stable. Isoproterenol stimulation further increased flow through the left internal mammary artery graft to 160 ml/min. This study suggests that the canine internal mammary artery is capable of substantial early increase in flow and can, in fact, support the entire left coronary circulation.

Animals↗
PubMed1988

Excellent patency and growth potential of internal mammary artery grafts in pediatric coronary artery bypass surgery. New evidence for a "live" conduit.

Coronary artery bypass grafting in pediatric patients provides a unique opportunity to evaluate the characteristics of graft material. Twelve pediatric patients with severe coronary artery involvement secondary to Kawasaki disease underwent coronary artery bypass grafting with internal mammary artery and autologous saphenous vein grafts. Eleven patients were boys and one was a girl; their ages ranged from 5 to 13 years (mean age +/- SD, 8.7 +/- 3.0 years). These 12 patients had 17 internal mammary artery and 11 autologous saphenous vein grafts with a mean value of 2.3 +/- 0.7 grafts per patient. Five patients underwent bilateral internal mammary artery grafting with or without concomitant autologous saphenous vein grafting. There was no mortality, and all patients are leading almost normal lives, although strenuous exercise is still prohibited for some. Biplanar cineangiography was performed before and 1 month after (early postoperative period) coronary artery bypass grafting in all patients and was repeated more than 1 year after (late postoperative period) bypass in eight patients. Changes in graft diameter and graft length were assessed by computer-assisted graphic analysis of 10 internal mammary artery grafts and of seven saphenous vein grafts between the early and late postoperative periods. Patency rates of saphenous vein grafts and of internal mammary artery grafts were 91% and 100%, respectively, at the early postoperative period (p = NS), and 50% and 100%, respectively, at the late postoperative period (p less than 0.05). In addition to the excellent patency of internal mammary artery grafts in the late postoperative period, an in situ internal mammary artery graft was found to have grown 125% in length with 112% body growth (112% body surface area) (r = 0.88, p less than 0.001) and to have enlarged 149% in diameter when the native coronary stenosis was tight. In contrast, the lengths of saphenous vein grafts either failed to change or were slightly decreased at the late postoperative period (p = NS). Growth potential of the internal mammary artery graft provides a new demonstration of the viability and adaptability of this graft. We conclude that the internal mammary artery graft is a "live" conduit with potential for growth and adaptation. This growth potential may be the most important reason for its excellent long-term patency, which suggests that in situ internal mammary artery grafts are the graft of choice for pediatric coronary artery bypass grafting.

Adolescent↗