- Email: [email protected]
Which stent to use for tracheobronchial stenoses: Metallic or silicone?
1512
CORRESPONDENCE
Ann Thorac Surg 1997;63;1511-6
Table 1. Patients' Characteristics" MICR (n 11)
CABG (n - 11)
p Value
57.3 + 1.9 18.2% 1.27 _+ 0.14 20.0 ± 2.2
61.4 _+ 3.5 36.4% 4.10 _+ 0 . 3 7 54.5 * 5.4
0.31 0.63 <0.0001 <0.0001
Variable Age (y) Sex (female) Number of grafts Ischemic time (mins)
~'Results are expressed as mean + standard error. Student's t test and Fisher's exact test were used to compare variables between the two groups. CABG - coronary artery bypass grafting; coronary, revascularization.
MICR- minimally invasive
frozen to 75°C until assayed. The level of cTnT was measured by using an enzyme immunoassay using the Enzym-Test Troponin-T on an E.S. 300 immunoassay analyzer (Boehringer Mannheim, Lewes, UK). Two-way analysis of variance and multiple range test was used to describe cTnT level changes over time. Variables between groups were compared with Student's t test and Fisher's exact test. Results were expressed as mean _+ standard error, and differences were considered significant at a probability level of p less than 0.05. Patients' characteristics are presented in Table 1. No patient received inotropic support during or after the operation, and none of them had any significant complication over the 72 hours of observation. In the MICR group the ST segment elevation during ischemic periods was 1.07 _+ 0.31 mm (range 0 to 4 ram) and the ischaemic time per anastomosis was 16.1 _+ 1.39 minutes (range, 12 to 28 minutes). Time changes of cTnT level are presented in Figure 1.
~
CABG MICR
Minimally invasive coronary revascularization without cardiopulmonary bypass was not associated with a raised cTnT level as compared with the baseline values. The comparison group, although not ideal due to more extensive coronary disease and longer ischemic periods imposed, was representative of the myocardial damage in uncomplicated routine coronary operations. The comparison between coronary artery bypass grafting and MICR therefore showed that myocardial damage in the latter was remarkably less than that acceptable for routine coronary cases. Collateral circulation developed in the setting of chronic coronary occlusion may be adequate for myocardial preservation during short periods (12 to 28 minutes) of normothermic regional ischemia. In conclusion, MICR may have a significant advantage over coronary artery bypass grafting with cardiopulmonary bypass, that of minimal myocardial damage, which could be of great importance especially in patients with low ejection fraction.
Leonidas K. Hadjinikolaou, MD Andrew S. Cohen, FRCS Helen Aitkenhead, MSc William Richmond, PhD Rex De L. Stanbridge, FRCS Cardiothoracic Department St. Mary's Hospital Praed StreeL London W2 1NY United Kingdom References 1. Ullyot DJ. Look Ma, no hands! Ann Thorac Surg 1996;61:10-1. 2. Akins CW, Boucher CA, Pohost GM. Preservation of interventricular septal function in patients having coronary artery bypass grafts without cardiopulmonary bypass. Am Heart J 1984; 107:304-9.
W h i c h Stent to U s e for T r a c h e o b r o n c h i a l S t e n o s e s : M e t a l l i c or S i l i c o n e ? To the Editor:
'$
cTnTo, gll))
=k
'~
2
po
lh
6h
24h
72h
time Fig 1. Time changes of troponin-T (cTnT) level in patients undergoing coronary artery bypass grafting (CABG) and minimally invasire coronary revascularization (MICR). Results are expressed as mean +_ standard error. Data were analyzed with two-way analysis of variance and multiple range test. Values between groups were compared with Student's t test (*statistically significant difference between groups at the corresponding time point; **statistically significant difference from the baseline value; po - preoperative.) © 1997 by The Society, of Thoracic Surgeons Published by Elsevier Science lnc
We read with interest the reported experience by Takamori and associates [1] on the use of a Gianturco stent for tracheobronchial stenoses secondary to esophageal carcinoma. Takamori and associates advocated the metallic stent because it could be inserted under local anesthesia and symptomatic relief was achieved in 8 of 12 patients (67%). Esophageal carcinoma is one of the most common cancers in Hong Kong, and over the last 3 years, we have inserted 17 silicone stents (Dumon Stent; Cometh, Marseille, France) in 15 patients with tracheobronchial stenoses resulting from esophageal carcinoma [2]. This was performed using total intravenous anesthesia (2,6-disopropylphenol or propofol; Zeneca, Macclesfield, Cheshire, UK) and assisted spontaneous ventilation. The stenoses were successfully dilated using the ventilating rigid bronchoscope (Efer-Dumon Bronchoscope; Efer, La Ciotat, France) in all cases. Tumor infiltration of the membranous trachea was observed in the majority of cases. One or two studded silicone stents (Dumon) were inserted using a dedicated introducer through the bronchoscope in each case. We saw no intraoperative complication or procedure-related mortality. All the patients had symptomatic relief (mean dyspnea relief by visual analogue scale, 7.8 on a scale of I to 10 with 10 being complete relief). All patients tolerated the procedure well. 0003-4975/97/$17.00
Ann Thorac Surg 1997;63;1511-6
In the absence of a prospective, randomized study, it would be difficult to conclude which stent, metallic or silicone, is better. However, we are impressed with our described technique (using total intravenous anesthesia and ventilating rigid bronchoscopy), which allows safe control of the airway and permits further intervention if need be. The studded silicone stent is easy to insert and remove and does not lead to the dreaded complication of trachea erosion or tumor/granulation growth between the wires, which is intrinsically associated with the Gianturco stent [3].
Anthony P. C. Yim, MD Victor J. Abdullah, FRCS Mohammad Bashar Izzat, FRCS Department of Surgery The Chinese University of Hong Kong Prince of Wales Hospital Shatin, NT Hong Kong e-maih [email protected] References 1. Takamori S, Fujita H, Hayashi, A, et al. Expandable metallic stents for tracheobronchial stenoses in esophageal cancer. Ann Thorac Surg 1996;62:844-7. 2. Yim APC, Abdullah V, Ho JKS, van Hasselt CA. Video assisted interventional bronchoscopy--the Hong Kong experience. Surg Endosc (in press). 3. Nomori H, Kobayashi R, Kodera K, Morinaga S, Ogawa K. Indications for an expandable metallic stent for tracheobronchial stenosis. Ann Thorac Surg 1993;56:1324-8.
Reply To the Editor: I thank Dr Yim and associates for their comments on our report of metallic stents for tracheobronchial stenoses in esophageal cancer [1]. My colleagues and I agree with their concern about the controversy of which stent, metallic or silicone, is better. Their technique of silicone stent insertion for tracheobronchial stenoses resulting from esophageal carcinoma is excellent. Although we have little experience in the use of the silicone stent, the technique using a rigid bronchoscope remains invasive and the procedure requires an experienced endoscopist and a skilled anesthesiologist. A Gianturco stent is easy to insert by using a flexible fiberscope u n d e r local anesthesia, which is favorable w h e n the patient is severely compromised. On the point of comparative cost, the metallic stent is inexpensive because the stent is made by ourselves, whereas the silicone stent is quite expensive. Tracheobronchial erosion or tumor/granulation growth between the wires, which is intrinsically associated with the Gianturco stent, is a disadvantage in p e r m a n e n t stent application. A silicone stent may be indicated for such a condition. We consider stenting to be palliative only and a local therapy for tracheobronchial stenoses; additional modalities such as irradiation, chemotherapy, and especially laser treatment are recomm e n d e d [2].
Shinzo Takamori, MD First Department of Surgery Kurume University School of Medicine 67 Asahi-machi Kurume 830, Japan © 1997 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
CORRESPONDENCE
1513
References 1. Takamori S, Fujita H, Hayashi A, et al. Expandable metallic stents for tracheobronchial stenoses in esophageal cancer. Ann Thorac Surg 1996;62:844-7. 2. McElvein RB. Treatment of malignant tracheobronchial obstruction. Ann Thorac Surg 1989;48:463-4.
Role of Intraoperative Autotransfusion After Cardiopulmonary Bypass To the Editor: I read with great interest the article by Kochamba and colleagues [1] regarding intraoperative autotransfusion after cardiopulmonary bypass (CPB). As in many preceding studies, a hemostatic benefit was not demonstrated that could explain the observed reduction in blood loss. Postoperative platelet counts, prothrombin times, and hematocrits were similar in the two patient groups. Unfortunately, there was no laboratory evidence documenting that heparin rebound was evaluated or treated before fresh frozen plasma administration occurred, as mandated by the transfusion algorithm. Like many clinicians, I have always been intrigued by the hemostatic benefit of autologously harvested blood reinfused after CPB. My colleagues and I [2] recently published an article that may, in part, help explain a poorly appreciated prohemostatic effect of autologous blood harvested preoperatively and then reinfused immediately after protamine administration following CPB. In our investigation, after heparinization and before CPB, venous blood {average, 4.9 mL/kg) was removed via an indwelling internal jugular catheter into a preservative-free plastic transfer pack unit and stored without agitation at room temperature. This autologous whole blood was then reinfused after systemic protamine reversal of heparin. Blood samples for analysis were drawn immediately before and 5 minutes after completion of the reinfusion. Autologous blood reinfusion appeared to be significantly related to increased hemoglobin, hematocrit, platelet count, fibrinogen, plasminogen, a n d antiplasmin levels. The prothrombin time and activated partial thromboplastin times decreased significantly, whereas activated clotting times and d-dimer levels were unchanged. Significant increases occurred in the following thromboelastography parameters: maximum amplitude, amplitude 60 minutes after the maximum amplitude, and whole blood clot lysis index. Reaction time and coagulation time were not statistically different from control values. It is my belief that additional investigations need to be carried out to further delineate the exact influence on the hemostatic mechanism of autologously harvested whole blood reinfusion after CPB. In our study, autologous blood administration appeared to modulate the activity of the fibrinolytic mechanism, as documented by alterations in biochemical markers of fibrinolytic activity, as well as thromboelastography. We observed significant increases in both A60 and whole blood clot lysis index (thromboelastographic markers indicating decreased fibrinolytic activity) after autologous blood reinfusion. Our preliminary findings suggest that autologous blood reinfusion may have beneficial effects on post-CPB fibrinolytic abnormalities. This improvement could result from an antifibrolytic activity of infused platelets (PAI-1) or, in part, to observed, although small increases in antiplasmin activity, even though the antiplasmin levels after reinfusion in our investigation remained below the normal range.
0003-49751971517.00
CORRESPONDENCE
Ann Thorac Surg 1997;63;1511-6
Table 1. Patients' Characteristics" MICR (n 11)
CABG (n - 11)
p Value
57.3 + 1.9 18.2% 1.27 _+ 0.14 20.0 ± 2.2
61.4 _+ 3.5 36.4% 4.10 _+ 0 . 3 7 54.5 * 5.4
0.31 0.63 <0.0001 <0.0001
Variable Age (y) Sex (female) Number of grafts Ischemic time (mins)
~'Results are expressed as mean + standard error. Student's t test and Fisher's exact test were used to compare variables between the two groups. CABG - coronary artery bypass grafting; coronary, revascularization.
MICR- minimally invasive
frozen to 75°C until assayed. The level of cTnT was measured by using an enzyme immunoassay using the Enzym-Test Troponin-T on an E.S. 300 immunoassay analyzer (Boehringer Mannheim, Lewes, UK). Two-way analysis of variance and multiple range test was used to describe cTnT level changes over time. Variables between groups were compared with Student's t test and Fisher's exact test. Results were expressed as mean _+ standard error, and differences were considered significant at a probability level of p less than 0.05. Patients' characteristics are presented in Table 1. No patient received inotropic support during or after the operation, and none of them had any significant complication over the 72 hours of observation. In the MICR group the ST segment elevation during ischemic periods was 1.07 _+ 0.31 mm (range 0 to 4 ram) and the ischaemic time per anastomosis was 16.1 _+ 1.39 minutes (range, 12 to 28 minutes). Time changes of cTnT level are presented in Figure 1.
~
CABG MICR
Minimally invasive coronary revascularization without cardiopulmonary bypass was not associated with a raised cTnT level as compared with the baseline values. The comparison group, although not ideal due to more extensive coronary disease and longer ischemic periods imposed, was representative of the myocardial damage in uncomplicated routine coronary operations. The comparison between coronary artery bypass grafting and MICR therefore showed that myocardial damage in the latter was remarkably less than that acceptable for routine coronary cases. Collateral circulation developed in the setting of chronic coronary occlusion may be adequate for myocardial preservation during short periods (12 to 28 minutes) of normothermic regional ischemia. In conclusion, MICR may have a significant advantage over coronary artery bypass grafting with cardiopulmonary bypass, that of minimal myocardial damage, which could be of great importance especially in patients with low ejection fraction.
Leonidas K. Hadjinikolaou, MD Andrew S. Cohen, FRCS Helen Aitkenhead, MSc William Richmond, PhD Rex De L. Stanbridge, FRCS Cardiothoracic Department St. Mary's Hospital Praed StreeL London W2 1NY United Kingdom References 1. Ullyot DJ. Look Ma, no hands! Ann Thorac Surg 1996;61:10-1. 2. Akins CW, Boucher CA, Pohost GM. Preservation of interventricular septal function in patients having coronary artery bypass grafts without cardiopulmonary bypass. Am Heart J 1984; 107:304-9.
W h i c h Stent to U s e for T r a c h e o b r o n c h i a l S t e n o s e s : M e t a l l i c or S i l i c o n e ? To the Editor:
'$
cTnTo, gll))
=k
'~
2
po
lh
6h
24h
72h
time Fig 1. Time changes of troponin-T (cTnT) level in patients undergoing coronary artery bypass grafting (CABG) and minimally invasire coronary revascularization (MICR). Results are expressed as mean +_ standard error. Data were analyzed with two-way analysis of variance and multiple range test. Values between groups were compared with Student's t test (*statistically significant difference between groups at the corresponding time point; **statistically significant difference from the baseline value; po - preoperative.) © 1997 by The Society, of Thoracic Surgeons Published by Elsevier Science lnc
We read with interest the reported experience by Takamori and associates [1] on the use of a Gianturco stent for tracheobronchial stenoses secondary to esophageal carcinoma. Takamori and associates advocated the metallic stent because it could be inserted under local anesthesia and symptomatic relief was achieved in 8 of 12 patients (67%). Esophageal carcinoma is one of the most common cancers in Hong Kong, and over the last 3 years, we have inserted 17 silicone stents (Dumon Stent; Cometh, Marseille, France) in 15 patients with tracheobronchial stenoses resulting from esophageal carcinoma [2]. This was performed using total intravenous anesthesia (2,6-disopropylphenol or propofol; Zeneca, Macclesfield, Cheshire, UK) and assisted spontaneous ventilation. The stenoses were successfully dilated using the ventilating rigid bronchoscope (Efer-Dumon Bronchoscope; Efer, La Ciotat, France) in all cases. Tumor infiltration of the membranous trachea was observed in the majority of cases. One or two studded silicone stents (Dumon) were inserted using a dedicated introducer through the bronchoscope in each case. We saw no intraoperative complication or procedure-related mortality. All the patients had symptomatic relief (mean dyspnea relief by visual analogue scale, 7.8 on a scale of I to 10 with 10 being complete relief). All patients tolerated the procedure well. 0003-4975/97/$17.00
Ann Thorac Surg 1997;63;1511-6
In the absence of a prospective, randomized study, it would be difficult to conclude which stent, metallic or silicone, is better. However, we are impressed with our described technique (using total intravenous anesthesia and ventilating rigid bronchoscopy), which allows safe control of the airway and permits further intervention if need be. The studded silicone stent is easy to insert and remove and does not lead to the dreaded complication of trachea erosion or tumor/granulation growth between the wires, which is intrinsically associated with the Gianturco stent [3].
Anthony P. C. Yim, MD Victor J. Abdullah, FRCS Mohammad Bashar Izzat, FRCS Department of Surgery The Chinese University of Hong Kong Prince of Wales Hospital Shatin, NT Hong Kong e-maih [email protected] References 1. Takamori S, Fujita H, Hayashi, A, et al. Expandable metallic stents for tracheobronchial stenoses in esophageal cancer. Ann Thorac Surg 1996;62:844-7. 2. Yim APC, Abdullah V, Ho JKS, van Hasselt CA. Video assisted interventional bronchoscopy--the Hong Kong experience. Surg Endosc (in press). 3. Nomori H, Kobayashi R, Kodera K, Morinaga S, Ogawa K. Indications for an expandable metallic stent for tracheobronchial stenosis. Ann Thorac Surg 1993;56:1324-8.
Reply To the Editor: I thank Dr Yim and associates for their comments on our report of metallic stents for tracheobronchial stenoses in esophageal cancer [1]. My colleagues and I agree with their concern about the controversy of which stent, metallic or silicone, is better. Their technique of silicone stent insertion for tracheobronchial stenoses resulting from esophageal carcinoma is excellent. Although we have little experience in the use of the silicone stent, the technique using a rigid bronchoscope remains invasive and the procedure requires an experienced endoscopist and a skilled anesthesiologist. A Gianturco stent is easy to insert by using a flexible fiberscope u n d e r local anesthesia, which is favorable w h e n the patient is severely compromised. On the point of comparative cost, the metallic stent is inexpensive because the stent is made by ourselves, whereas the silicone stent is quite expensive. Tracheobronchial erosion or tumor/granulation growth between the wires, which is intrinsically associated with the Gianturco stent, is a disadvantage in p e r m a n e n t stent application. A silicone stent may be indicated for such a condition. We consider stenting to be palliative only and a local therapy for tracheobronchial stenoses; additional modalities such as irradiation, chemotherapy, and especially laser treatment are recomm e n d e d [2].
Shinzo Takamori, MD First Department of Surgery Kurume University School of Medicine 67 Asahi-machi Kurume 830, Japan © 1997 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
CORRESPONDENCE
1513
References 1. Takamori S, Fujita H, Hayashi A, et al. Expandable metallic stents for tracheobronchial stenoses in esophageal cancer. Ann Thorac Surg 1996;62:844-7. 2. McElvein RB. Treatment of malignant tracheobronchial obstruction. Ann Thorac Surg 1989;48:463-4.
Role of Intraoperative Autotransfusion After Cardiopulmonary Bypass To the Editor: I read with great interest the article by Kochamba and colleagues [1] regarding intraoperative autotransfusion after cardiopulmonary bypass (CPB). As in many preceding studies, a hemostatic benefit was not demonstrated that could explain the observed reduction in blood loss. Postoperative platelet counts, prothrombin times, and hematocrits were similar in the two patient groups. Unfortunately, there was no laboratory evidence documenting that heparin rebound was evaluated or treated before fresh frozen plasma administration occurred, as mandated by the transfusion algorithm. Like many clinicians, I have always been intrigued by the hemostatic benefit of autologously harvested blood reinfused after CPB. My colleagues and I [2] recently published an article that may, in part, help explain a poorly appreciated prohemostatic effect of autologous blood harvested preoperatively and then reinfused immediately after protamine administration following CPB. In our investigation, after heparinization and before CPB, venous blood {average, 4.9 mL/kg) was removed via an indwelling internal jugular catheter into a preservative-free plastic transfer pack unit and stored without agitation at room temperature. This autologous whole blood was then reinfused after systemic protamine reversal of heparin. Blood samples for analysis were drawn immediately before and 5 minutes after completion of the reinfusion. Autologous blood reinfusion appeared to be significantly related to increased hemoglobin, hematocrit, platelet count, fibrinogen, plasminogen, a n d antiplasmin levels. The prothrombin time and activated partial thromboplastin times decreased significantly, whereas activated clotting times and d-dimer levels were unchanged. Significant increases occurred in the following thromboelastography parameters: maximum amplitude, amplitude 60 minutes after the maximum amplitude, and whole blood clot lysis index. Reaction time and coagulation time were not statistically different from control values. It is my belief that additional investigations need to be carried out to further delineate the exact influence on the hemostatic mechanism of autologously harvested whole blood reinfusion after CPB. In our study, autologous blood administration appeared to modulate the activity of the fibrinolytic mechanism, as documented by alterations in biochemical markers of fibrinolytic activity, as well as thromboelastography. We observed significant increases in both A60 and whole blood clot lysis index (thromboelastographic markers indicating decreased fibrinolytic activity) after autologous blood reinfusion. Our preliminary findings suggest that autologous blood reinfusion may have beneficial effects on post-CPB fibrinolytic abnormalities. This improvement could result from an antifibrolytic activity of infused platelets (PAI-1) or, in part, to observed, although small increases in antiplasmin activity, even though the antiplasmin levels after reinfusion in our investigation remained below the normal range.
0003-49751971517.00