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Effects of intracoronary urokinase during acute myocardial infarction
LETTERS* EFFECTS
OF
UROKINASE
INTRACORONARY DURING
MYOCARDIAL
ACUTE
INFARCTION
The report from Hamamatsu City, Japan, in the May 1984 issue of the JournaP regarding intracoronary urokinase in 32 consecutive patients was confusing. The authors defined percutaneous transluminal coronary angioplasty as being synonymous with the infusion of intracoronary urokinase. Percutaneous transluminal coronary angioplasty using a balloon dilatation catheter (as the term commonly denotes in the U.S.) was not performed. They mentioned variations in opening rate with varying doses of urokinase. The number of patients is small and it is hard to know if these variations in opening rate are significant. The authors did not characterize their population in terms of the coronary artery involved, presence or absence of collaterals and proximal or distal narrowing, all of which have significant impact on varying opening rates. The authors did not state whether the urokinase used was from a urinary or kidney tissue source and how homogeneous the preparation was. No data were given regarding the incidence of systemic fibrinolysis. This would be of interest given the report by
Tennant et al2 of significantly greater fibrinolysis in patients given streptokinase than in those given urokinase in equally efficacious doses. No information was provided regarding recanalization followed by reocclusion. Their observations regarding ventricular function are interesting. It is important to know if these measurements were carried out in a blinded fashion. Yasuno et al implied that concommitant use of glucose, potassium and insulin may be responsible for improvement in ventricular function. Certainly the ejection fraction and regional wall shortening showed dramatic improvement in group A, but the numbers are small. It would be of interest to know if the systemic vascular resistances were calculated during these studies and if there was any significant change in either left-sided cardiac filling pressures or systemic vascular resistances. W. Barton Campbell, Me
Nashville, Tennessee
1. YasunoM, Salto Y, tshldaM, SuzukiK, EndoS, Takaha~hl M. Effects of percutaneoustransluminalcoronary angioplasty:intracoronarythrombolyslswith urokinase in acutemyocardialinfarction. Am J Cardlol 1984;53: 1217-1220. 2. TennantSN, DixonJ, VenableTC, Page HLJ, RoachA, Katser AB, Frederlksen R, Tacogue L, Kaplan P, Babu NS, AndersonEE, Wooten E, JennlngsHS III, Brelnlg J, CampbellWB. In~acoronarythrombolysisin patients with acutemyocardialinfarction:comparisonof the efficacy of urokinase with streptokinase. Circulation
1984;69:756-760, • Letters (from the United States) concerning a particular article in the Journal must be received within 2 months of the article's publication, and should be limited (with rare exceptions) to 2 double-spaced typewritten pages. Two copies must be submitted.
REPLY: We defined "coronary angioplasty" es synonymous with "coronary recanalization therapy" and not completely synonymous with "infusion of intracoronary urokinase",
because we used mechanical reperfusion techniques with soft guidewire in combination with urokinase infusion in 2 patients. The number of patients was small. However, we indicated that the dose of urokinase was an important determinant of reperfusion, and a larger dose of urokinase (>240,000 U) could achieve reperfusion at a significantly higher rate (p <0.005). We have not found that the coronary anatomy, as indicated by Campbell, has influence on the opening rate. It is possible that an even smaller dose of urokinase as studied by Tennant et al could recanalize the occluded vessel by an infusion time such as 1 or 2 hours. However, we believe that our higher infusion rate (24,000 U/rain) can save significant time in opening the occluded artery, and is advantageous in both salvaging the jeopardized myocardium and managing the catheterization laboratory. We used highly purified (98%) urokinase from a urinary source and have not experienced major hemorrhagic complications related to systemic fibrinolysis as long as the total dose was within 960,000 units. We showed remarkable improvement in both global and regional left ventricular (LV) contractile function in group A. These measurements were performed by 2 observers in a blinded fashion and comparison of data showed a good correlation (r = 0.93) for both measurements. LV filling pressures showed significant improvements during the chronic stage in not only group A patients but also in group B and C patients. Thus, we believe that wall motion analysis is a more reliable method of evaluating the effect of coronary recanalization therapy on LV function.
CORRECTIONS In the D e c e m b e r 1, 1984 issue on page 1172, the Letter to the Editor written by Dr. Paolo Palatini was incorrectly titled: QT/QS2 Ratio as Index of A u t o m a t i c Tone. It should read:
QT/QS2 Ratio as Index of A u t o n o m i c Tone.
In the October 1, 1984 issue on page 764 (Fleg AL and Lakatta EG: Prevalence and Prognosis of Exercise-Induced Nonsustained Ventricular Tachycardia in Apparently Healthy Volunteers), 6 references w e r e omitted from the article: 15. Ekblom B, Hadley LH, Day WC. Occurrence and reproducibility of exercise-induced ventricular ectopy in normal subjects. Am J Cardiol 1979;43:35-40. 16. Clarke JM, Shelton JR, Hamer J, Taylor S, Yenning GR. The rhythm of the normal human heart. Lancet 1976;2:508-512. 17. Raftery EB, Cashmann PMM. Long-termrecordingof the electrocardiogramin a normal population.Postgrad Med J 1976;52(suppl 7):32-37. 13. KosUs JB, McCrone K, Moreyra AE, Gotzoyannls S, Aglllz N, Nataralan N, Kuo P. Premature ventricular complications in the absence of identifiable heart disease. Circulation 1981;63:1351-1356. 19. Fleg JL, Kennedy HL. Cardiac arrhythmias in a healthy elderly population:detection by 24-hour ambulatory electrocardiography. Chest 1982;81:302-307. 29. White NK, Edwards JE, Dry T3. The relationship of the degree of coronary atherosclerosis with age in men. Circulation 1950; 1:645-654.
1396
Masao Yasuno, MD
Hamamatsu City, Japan
OF
UROKINASE
INTRACORONARY DURING
MYOCARDIAL
ACUTE
INFARCTION
The report from Hamamatsu City, Japan, in the May 1984 issue of the JournaP regarding intracoronary urokinase in 32 consecutive patients was confusing. The authors defined percutaneous transluminal coronary angioplasty as being synonymous with the infusion of intracoronary urokinase. Percutaneous transluminal coronary angioplasty using a balloon dilatation catheter (as the term commonly denotes in the U.S.) was not performed. They mentioned variations in opening rate with varying doses of urokinase. The number of patients is small and it is hard to know if these variations in opening rate are significant. The authors did not characterize their population in terms of the coronary artery involved, presence or absence of collaterals and proximal or distal narrowing, all of which have significant impact on varying opening rates. The authors did not state whether the urokinase used was from a urinary or kidney tissue source and how homogeneous the preparation was. No data were given regarding the incidence of systemic fibrinolysis. This would be of interest given the report by
Tennant et al2 of significantly greater fibrinolysis in patients given streptokinase than in those given urokinase in equally efficacious doses. No information was provided regarding recanalization followed by reocclusion. Their observations regarding ventricular function are interesting. It is important to know if these measurements were carried out in a blinded fashion. Yasuno et al implied that concommitant use of glucose, potassium and insulin may be responsible for improvement in ventricular function. Certainly the ejection fraction and regional wall shortening showed dramatic improvement in group A, but the numbers are small. It would be of interest to know if the systemic vascular resistances were calculated during these studies and if there was any significant change in either left-sided cardiac filling pressures or systemic vascular resistances. W. Barton Campbell, Me
Nashville, Tennessee
1. YasunoM, Salto Y, tshldaM, SuzukiK, EndoS, Takaha~hl M. Effects of percutaneoustransluminalcoronary angioplasty:intracoronarythrombolyslswith urokinase in acutemyocardialinfarction. Am J Cardlol 1984;53: 1217-1220. 2. TennantSN, DixonJ, VenableTC, Page HLJ, RoachA, Katser AB, Frederlksen R, Tacogue L, Kaplan P, Babu NS, AndersonEE, Wooten E, JennlngsHS III, Brelnlg J, CampbellWB. In~acoronarythrombolysisin patients with acutemyocardialinfarction:comparisonof the efficacy of urokinase with streptokinase. Circulation
1984;69:756-760, • Letters (from the United States) concerning a particular article in the Journal must be received within 2 months of the article's publication, and should be limited (with rare exceptions) to 2 double-spaced typewritten pages. Two copies must be submitted.
REPLY: We defined "coronary angioplasty" es synonymous with "coronary recanalization therapy" and not completely synonymous with "infusion of intracoronary urokinase",
because we used mechanical reperfusion techniques with soft guidewire in combination with urokinase infusion in 2 patients. The number of patients was small. However, we indicated that the dose of urokinase was an important determinant of reperfusion, and a larger dose of urokinase (>240,000 U) could achieve reperfusion at a significantly higher rate (p <0.005). We have not found that the coronary anatomy, as indicated by Campbell, has influence on the opening rate. It is possible that an even smaller dose of urokinase as studied by Tennant et al could recanalize the occluded vessel by an infusion time such as 1 or 2 hours. However, we believe that our higher infusion rate (24,000 U/rain) can save significant time in opening the occluded artery, and is advantageous in both salvaging the jeopardized myocardium and managing the catheterization laboratory. We used highly purified (98%) urokinase from a urinary source and have not experienced major hemorrhagic complications related to systemic fibrinolysis as long as the total dose was within 960,000 units. We showed remarkable improvement in both global and regional left ventricular (LV) contractile function in group A. These measurements were performed by 2 observers in a blinded fashion and comparison of data showed a good correlation (r = 0.93) for both measurements. LV filling pressures showed significant improvements during the chronic stage in not only group A patients but also in group B and C patients. Thus, we believe that wall motion analysis is a more reliable method of evaluating the effect of coronary recanalization therapy on LV function.
CORRECTIONS In the D e c e m b e r 1, 1984 issue on page 1172, the Letter to the Editor written by Dr. Paolo Palatini was incorrectly titled: QT/QS2 Ratio as Index of A u t o m a t i c Tone. It should read:
QT/QS2 Ratio as Index of A u t o n o m i c Tone.
In the October 1, 1984 issue on page 764 (Fleg AL and Lakatta EG: Prevalence and Prognosis of Exercise-Induced Nonsustained Ventricular Tachycardia in Apparently Healthy Volunteers), 6 references w e r e omitted from the article: 15. Ekblom B, Hadley LH, Day WC. Occurrence and reproducibility of exercise-induced ventricular ectopy in normal subjects. Am J Cardiol 1979;43:35-40. 16. Clarke JM, Shelton JR, Hamer J, Taylor S, Yenning GR. The rhythm of the normal human heart. Lancet 1976;2:508-512. 17. Raftery EB, Cashmann PMM. Long-termrecordingof the electrocardiogramin a normal population.Postgrad Med J 1976;52(suppl 7):32-37. 13. KosUs JB, McCrone K, Moreyra AE, Gotzoyannls S, Aglllz N, Nataralan N, Kuo P. Premature ventricular complications in the absence of identifiable heart disease. Circulation 1981;63:1351-1356. 19. Fleg JL, Kennedy HL. Cardiac arrhythmias in a healthy elderly population:detection by 24-hour ambulatory electrocardiography. Chest 1982;81:302-307. 29. White NK, Edwards JE, Dry T3. The relationship of the degree of coronary atherosclerosis with age in men. Circulation 1950; 1:645-654.
1396
Masao Yasuno, MD
Hamamatsu City, Japan