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Clot
REVIEW OF RECENT BOOKS
Clot By lames L. Tullis, M.D. Charles C Thomas, Springfield, I L , 1926 572 p p , illustrated, $39.50 Reviewed by Alan Marty, M.D. Since surgical patients frequently exhibit excessive bleeding or clotting, no surgeon can deny the importance of keeping abreast of this field. In translating this goal into reality, however, at least two difficulties emerge: learning the coagulation jargon and separating the surgically relevant facts about hemostasis from the material of pure research interest. This text helps overcome the first difficulty by supplying both a glossary and an illuminating review of the historical reasons for the present nomenclature. Despite such cognitive aids, however, the author’s refusal to oversimplify-indeed his compulsion to include all the exceptions to the rules-at times proves frustrating to the nonspecialist reader. This leads to an unsatisfactory resolution of the second difficulty. For example, it is somewhat confusing to read: “Thromboembolic diseases are rare in thyrotoxicosis despite a several-fold increase in concentration of circulating factor VIII. Despite these findings, the administration of thyroid tends to improve capillary fragility, whereas antithyroid drugs worsen it. Paradoxically, total ablation of the thyroid protects against bleeding.“ On the more communicative side, the chapter titled “Acquired Hypoprothrombinemia in the Coagulant Chop-suey of Cirrhosis” clearly explains the four main hemostatic functions of the liver: synthesis of clotting factors, removal of activated clotting factors, removal of proteolytic plasmin degradation products, and partial control of platelet function and numbers. It then suggests how to identify potential hemorrhagic syndromes, e.g., primary fibrinogenolysis, and how to correct them (with eaminocaproic acid) prior to operation. New developments applicable to cardiothoracic surgery patients are widely scattered throughout the book. In patients facing emergency surgery who have been receiving warfarin, for example, the rarely necessary use of prothrombin concentrate infusion is discussed. Endogenous inhibitors of clotting, especially prominent in patients on warfarin therapy and in some patients exposed to inadequate hepatic perfusion after open-heart surgery, emerge as possible causes of previously unexplained bleeding. Other mysteries, such as why intravascular dotting usually remains a local phenomenon (due to natural inhibitors like antithrombin 111) or how radiocontrast agents can induce thrombosis (by destabilization and precipitation of fibrinogen) or why patients with blood group A may be predisposed to thrombosis 272
(due to higher levels of factors VIII, MI,11, and X and lower levels of antithrombin 111) are also well explained. Other relevant topics include a new screening test for estrogen contraceptive hypercoagulability, six reasons why smoking should exacerbate coronary artery disease, and five reasons why postoperative patients exhibit hypercoagulability. Since long-term studies show that prothrombin tests usually fall into the therapeutic range only 55 to 65% of the time, the effect of diet and drugs on warfarin dosage is clearly outlined. Ignoring the controversy over whether beef lung or pork intestine heparin is best, the author discusses the more important concept of the human variability in hemostatic response to heparin. With a standard dose of 40,000 units per 24 hours, as many as 25% of patients will show no heparin activity at all! This is not a text for all thoracic surgeons. It will appeal to those particularly motivated to understand more about the multifactorial complexity surrounding hemostatic problems. Portland, O R
Clot By lames L. Tullis, M.D. Charles C Thomas, Springfield, I L , 1926 572 p p , illustrated, $39.50 Reviewed by Alan Marty, M.D. Since surgical patients frequently exhibit excessive bleeding or clotting, no surgeon can deny the importance of keeping abreast of this field. In translating this goal into reality, however, at least two difficulties emerge: learning the coagulation jargon and separating the surgically relevant facts about hemostasis from the material of pure research interest. This text helps overcome the first difficulty by supplying both a glossary and an illuminating review of the historical reasons for the present nomenclature. Despite such cognitive aids, however, the author’s refusal to oversimplify-indeed his compulsion to include all the exceptions to the rules-at times proves frustrating to the nonspecialist reader. This leads to an unsatisfactory resolution of the second difficulty. For example, it is somewhat confusing to read: “Thromboembolic diseases are rare in thyrotoxicosis despite a several-fold increase in concentration of circulating factor VIII. Despite these findings, the administration of thyroid tends to improve capillary fragility, whereas antithyroid drugs worsen it. Paradoxically, total ablation of the thyroid protects against bleeding.“ On the more communicative side, the chapter titled “Acquired Hypoprothrombinemia in the Coagulant Chop-suey of Cirrhosis” clearly explains the four main hemostatic functions of the liver: synthesis of clotting factors, removal of activated clotting factors, removal of proteolytic plasmin degradation products, and partial control of platelet function and numbers. It then suggests how to identify potential hemorrhagic syndromes, e.g., primary fibrinogenolysis, and how to correct them (with eaminocaproic acid) prior to operation. New developments applicable to cardiothoracic surgery patients are widely scattered throughout the book. In patients facing emergency surgery who have been receiving warfarin, for example, the rarely necessary use of prothrombin concentrate infusion is discussed. Endogenous inhibitors of clotting, especially prominent in patients on warfarin therapy and in some patients exposed to inadequate hepatic perfusion after open-heart surgery, emerge as possible causes of previously unexplained bleeding. Other mysteries, such as why intravascular dotting usually remains a local phenomenon (due to natural inhibitors like antithrombin 111) or how radiocontrast agents can induce thrombosis (by destabilization and precipitation of fibrinogen) or why patients with blood group A may be predisposed to thrombosis 272
(due to higher levels of factors VIII, MI,11, and X and lower levels of antithrombin 111) are also well explained. Other relevant topics include a new screening test for estrogen contraceptive hypercoagulability, six reasons why smoking should exacerbate coronary artery disease, and five reasons why postoperative patients exhibit hypercoagulability. Since long-term studies show that prothrombin tests usually fall into the therapeutic range only 55 to 65% of the time, the effect of diet and drugs on warfarin dosage is clearly outlined. Ignoring the controversy over whether beef lung or pork intestine heparin is best, the author discusses the more important concept of the human variability in hemostatic response to heparin. With a standard dose of 40,000 units per 24 hours, as many as 25% of patients will show no heparin activity at all! This is not a text for all thoracic surgeons. It will appeal to those particularly motivated to understand more about the multifactorial complexity surrounding hemostatic problems. Portland, O R