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PubMed1983

Management of left ventricular rupture complicating myocardial infarction.

Rupture of the left ventricle secondary to myocardial infarction may occur more often than is suspected. More time than anticipated may be available between rupture and catastrophic deterioration. Hemodynamic stabilization, diagnostic studies, and surgical treatment can be successfully undertaken. Four patients have been successfully treated in our institution. Rupture occurred from 1 to 14 days after infarction. Persistent chest pain was present in all. All were hemodynamically unstable and all stabilized with counterpulsation. One patient was in cardiogenic shock, two had a cardiac arrest, and one presented with cardiac tamponade requiring two emergency pericardiocenteses. Coronary arteriography was done in all four patients. Surgical management consisted of infarctectomy and repair of the ventricular rupture. Additionally, a single aortacoronary bypass graft was needed in two patients and repair of a ventricular septal rupture was necessary in a third. There was no operative mortality. One patient drowned 1 year later. We conclude that successful surgical management requires (1) suspicion of ventricular rupture, (2) hemodynamic stabilization by counterpulsation, (3) coronary arteriography, and (4) combined infarctectomy and repair with revascularization.

Aged↗
PubMed1983

Femorofemoral bypass for temporary cardiac support in heart surgery.

Temporary femorofemoral bypass, combined with intra-aortic balloon pump counterpulsation, was used as a final resort to salvage the life of patients with extremely low cardiac output at the end of cardiopulmonary bypass and in patients who had cardiac arrest perioperatively who were unresponsive to conventional methods of resuscitation. Eight of 15 patients survived initially, 7 of them left hospital and remain well. These data are comparable to results obtained with the newly developed, but not readily available, left ventricular assist devices. The combination of femorofemoral bypass and intra-aortic balloon pump counterpulsation represents an important practical alternative as it can be used successfully for temporary cardiac support in critical situations, is potentially life-saving and is readily available at any cardiac centre at minimal cost.

Assisted Circulation↗
PubMed1984

[Method of devising a muscle pump for assisted circulation].

The authors have proposed a model of the blood pump from the skeletal automuscles of the body for carrying out aortal counterpulsation under experimental conditions. The pump is run by means of direct electric stimulation of the muscle. Have demonstrated that it is possible in principle to design a completely implanted small system of aortal counterpulsation.

Assisted Circulation↗
PubMed1982

[The effect of intra-aortic balloon pumping in experimental ischemic heart disease].

The effect of intraaortic balloon counterpulsation (IABP) was investigated in normal dogs and after production of ischemic myocardial damage of various extent. Pharmacologic isolation of the heart and ligation of the left anterior descending coronary artery at different levels produced ischemia of the distal third (preparation type 1), distal half (preparation type 2), and distal two-thirds (preparation type 3) of the left ventricular fee wall. The degree of left heart failure (LVF 1 - 3) correlated with the extent of the ischemic damage and was defined by characteristic hemodynamic and metabolic parameters. IABP was most effective when the ischemic damage of the left ventricle was limited and counterpulsation was instituted before significant heart failure developed. When the distal half of the left ventricular free wall became nonfunctional hemodynamic stabilisation remained pump-dependent; to improve survival immediate revascularization of the ischemic area is required. With extensive loss of functional myocardium IABP could merely delay irreversible cardiogenic shock. The experimental data suggest that IABP should be instituted before the blood pressure fall exceeds 25% of its original level. At the stage of profound cardiogenic shock IABP cannot improve survival significantly.

Animals↗
PubMed1978

[Possibilities of treatment in acute failure of the right heart].

Acute right heart failure can be influenced positively by means of right-sided respectively left-sided intraventricular balloon pump and the intraaortic counterpulsation. Yet, due to a narrow safety margin one should not try the right-sided intraventricular balloon pump in humans. Left-sided intraventricular balloon pumping immediately enhances cardiac output by 20--30%; the myocardial blood-flow to the subendocardium increases by 50%; finally the myocardial oxygen supply improves. Balloon inflation only during ejection time is demanded. So, up to 6 hours, properly timed left intraventricular balloon pumping does not damage left ventricular dimensions. The use of the intraaortic balloon pump was without problems. This pump device increases myocardial bloodflow to the subendocardium most effectively. There is a broad safety margin, too. Intraaortic counterpulsation should be started as soon as acute right heart failure is evident.

Heart Failure↗
PubMed1981

[Use of the intra-aortic balloon pump in treating severe cardiac contusions (an experimental study)].

In experiments on 20 dogs the authors studied haemodynamics and the myocardial contractility after severe contusion of the heart treated by counterpulsation with intraaortic balloon pump. The heart contusion leads rapidly to a marked decrease in the contractile function of the myocardium and to the development of the hypodynamic syndrome. If untreated, the trauma leads to ventricular fibrillation and death of animals 1-1 1/2 h after contusion. Counterpulsation started 30-45 min after trauma and lasting 1 1/2-2 1/2 h prevented ventricular fibrillation and improved the myocardial function.

Animals↗
PubMed1995

Chaotic behavior of hemodynamics with ventricular assist system.

In order to analyze hemodynamic parameters during left ventricular assistance as an entity and not as decomposed parts, non-linear mathematical techniques were utilized. Pneumatically actuated ventricular assist systems (VAS) were implanted as left heart bypasses in acute animal experiments, using healthy adult mongrel dogs. By the use of the non-linear mathematical technique, the arterial blood pressure waveform (AP) was embedded into the four-dimensional phase space and projected into the three-dimensional phase space. The Lyapunov numerical method was used as an adjunct to the graphical analysis of the state space. The phase portrait of the attractor showed a complex structure; a three dimensional solid torus with a screw type structure as a part, suggesting deterministic chaos in the AP without left ventricular assistance. Positive lyapunov exponents confirmed the existence of chaos. During counterpulsation mode left ventricular assistance, the phase portrait of the attractor showed a more complex structure, and positive Lyapunov exponents suggested a greater dimensional deterministic chaos. However, non-structured patterns were seen in the phase space during internal mode VAS driving, suggesting the possibility of dissipative dynamics in the four dimensional phase space. These results suggest that the cardiovascular system with counterpulsation mode VAS driving is in a homeochaotic state, which is thought to be a flexible and intelligent control system. And there is greater dimensional complex dynamics in the circulatory regulatory system with VAD during internal mode assistance.

Animals↗
PubMedDate not supplied

Concepts in the application of pneumatic ventricular assist devices for ischemic myocardial injury.

The clinical results of "bridge-to-recovery" from ischemic myocardial injury using pneumatic ventricular assist devices (VADs) have been disappointing, because no significant improvement in the hospital discharge rate (25%) has been observed during the past 10 years. Interestingly, similar results have been reported using the less sophisticated and more widely available centrifugal pumps. It is well recognized that appropriate patient selection and early device implantation are important determinants of patient survival; however, it is less clear why there is a lack of difference in the results between pneumatic VADs and the centrifugal pumps. The reasons for the lack of difference in the results between pneumatic VADs and centrifugal pumps are multifactorial, and to some extent may be due to a conservative approach in the application of the more capable pneumatic VADs. In an effort to provide a more effective approach to the clinical application of pneumatic VADs for bridge-to-recovery, two pneumatic devices (the Jarvik 7-70 total artificial heart and the Symbion acute VAD) were functionally characterized using an in vitro mock circulatory system. The performance under pneumatic VAD asynchronous pumping compared to electrocardiogram synchronous counterpulsation was also evaluated. Based upon the results obtained, a two phase approach was developed. In the initial phase (i.e., the first 12-48 hrs), device output is maximized through asynchronous pumping to rapidly reverse the effects of cardiogenic shock. During the second phase (i.e., after hemodynamic stabilization and early evidence of end-organ recovery), electrocardiogram synchronous counterpulsation is used to focus more specifically on recovery of the heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1976

Mechanical and surgical interventions for the reduction of myocardial ischemia.

To reduce myocardial ischemia effectively, mechanical or surgical interventions must achieve either augmentation in coronary blood flow, a reduction in myocardial oxygen demand, or a combination of both. Coronary bypass graft procedures can achieve an immediate augmentation in coronary blood flow distally through the involved vessel and thereby improve myocardial perfusion and oxygen delivery and thus have the potential for reversing myocardial ischemia both acutely and for the long term. Although myocardial revascularization may resolve the ventricular functional alterations associated with acute myocardial ischemia it remains uncertain whether revascularization can reverse ischemic myocardial cellular injury and in what time framework, as related to reversible vs. irreversible ischemic cellular changes. Mechanical circulatory assistance (MCA) using diastolic counterpulsation effectively reduces myocardial ischemia by the physiologic mechanisms of 1) decrease in left ventricular after-load and left ventricular wall tension, 2) improvement is cardiac output by diastolic counterpulsation and 3) augmentation of coronary blood flow by diastolic pressure augmentation. The most effective indication for either MCA or myocardial revascularization is for interruption of myocardial ischemia prior to the development of infarction. Clinical sudies have demonstrated that acute myocardial ischemia can be effectively interrupted by intraaortic balloon pumping (IABP) including reversal of left ventricular dysfunction associated with acute myocardial ischemia. In most instances, cessation of IABP resulted in recurrence of myocardial ischemia indicating the need for urgent revascularization surgery. In the management of medically refractory myocardial ischemia. IABP has been effective in complete suppression of ischemia in 80 percent and resulted in marked improvement in all, allowing safe revascularization surgery with an operative mortality in the range of 5% and perioperative myocardial infarction incidence of 2%. In patients with acute myocardial infarction and cardiogenic shock (AMI-CS), IABP can resolve CS in 75 percent. The combination of IABP and surgery has resulted in survival approaching 45 percent indicative of a significant improvement in salvage in this group of patients where expected mortality approaches 100 percent.

Assisted Circulation↗
PubMed1993

[The experimental study of the double intra aortic balloon (DIAB) pumping].

In vitro and animal experiments showed that the double intra aortic balloon (DIAB) pumping can provide 30% greater blood flow to the coronary arteries than does a single intra aortic balloon (SIAB) pumping of the same volume during counterpulsation. It significantly improves the hemodynamic parameters so as to raise the efficiency of the counterpulsation. The results are consistent with computer studies.

Animals↗
PubMed1993

Iatrogenic vascular trauma associated with intra-aortic balloon pumping: identification of risk factors.

The most important noncardiac consequence of use of the intra-aortic balloon pump (IABP) is associated iatrogenic vascular trauma. A retrospective analysis was undertaken of all patients at our institution (n = 90, mean age 60 years) who had insertion of an IABP over a 10-year period to assess the possibility of preoperative identification of patients at high risk of IABP associated vascular injury. Catheters were introduced via the common femoral artery (n = 84; 30 percutaneous, 4 open Seldinger technique, 50 via a dacron sleeve), external iliac artery (n = 2), and ascending aorta (n = 4). Thirty patients (33.3%) developed one or more complications, with 25 vascular complications, six major septic complications, and four deaths. Variables identified as significant risk factors for IABP complications were female gender (P < 0.01) and concomitant peripheral vascular disease (P < 0.05). Site of insertion, method or difficulty of insertion, age, duration of counterpulsation, and use of anticoagulation and antibiotics did not significantly affect the incidence of vascular complications (P > 0.05). In conclusion, prior to cardiac surgery, we recommend screening for peripheral vascular disease to identify patients at increased risk of complications should IABP counterpulsation be required. Ankle/brachial systolic pressure indices may be used to detect subclinical disease.

Adult↗
PubMed1996

[Survival of a patient with postinfarction ventricular septal defect following venoarterial bypass with centrifugal pump and reoperation for residual shunt].

A 61-year-old man was hospitalized because of circulatory collapse due to postinfarction ventricular septal defect. As his hemodynamic condition deteriorated despite intraaortic counterpulsation, he underwent patch closure of VSP and patch reconstruction of the anterior left ventricular wall concomitant with coronary artery bypass grafting to the circumflex lesion immediately after admission. Femorofemoral circulatory assist with centrifugal pump was necessitated to wean from cardiopulmonary bypass because of severe left ventricular dysfunction. Circulatory assist was controlled to maintain mixed venous oxygen saturation of more than 70% under mild hypothermia. On the second postoperative day (POD), increased oxygen saturation from right atrium to pulmonary artery developed (Qp/Qs = 2.1). Further surgery was performed on an emergency basis for additional patch closure of VSP. Then he was successfully weaned from cardiopulmonary bypass successfully. The patient was extubated on the 14th POD and was ambulatory when he discharged on the 56th POD. Immediate surgical intervention should be performed for the patient with postinfarction ventricular septal defect when the hemodynamic state deteriorates under intraaortic counterpulsation.

Assisted Circulation↗
PubMed1996

Caring for the intra-aortic balloon pump patient. Most frequently asked nursing questions.

IAB counterpulsation poses specific nursing issues and challenges. The patient's arterial pressure reference points are expanded to five components as opposed to the usual systole and diastole. It is, therefore, crucial that procedures be developed that address issues such as computation of mean arterial pressure and documentation and titration of drips through the use of the 5 waveform components of the IABP patient. Peripheral vascular assessment is most important because of the potential for compromised flow. The ankle/arm index can be used as an objective measurement to quantify perfusion. Balloon inflation during diastole normally generates the highest pressure point in the counterpulsation cycle. Various factors can lower the magnitude of augmentation, and these need to be included in troubleshooting assessments.

Critical Care↗
PubMed1976

Surgical management of life-threatening coronary artery disease: experience in 18 consecutive patients with left main trunk or equivalent coronary artery obstruction associated with an obstructed or a nondominant right coronary artery.

Eighteen patients with obstruction of the left main trunk or equivalent coronary artery associated with an obstructed or a nondominant right coronary artery were studied. All patients had coronary artery bypass surgery because of their symptoms and coronary anatomy. Five patients had coronary artery bypass without the use of preoperative elective intra-aortic balloon counterpulsation, and 3 of these patients had cardiac arrest prior to insertion of the grafts. The other 13 patients received elective intra-aortic balloon counterpulsation prior to induction of anesthesia and cannulation. None in this second group of patients developed any hypotensive episodes or cardiac arrest, and all have done well following the bypass operation. This experience suggests that the use of elective preoperative intra-aortic balloon assist in patients who have a very critical coronary artery obstruction is indicated in view of the high incidence of cardiac arrest observed in patients who did not receive the preoperative elective intra-aortic balloon support.

Adult↗
PubMed1991

Central venous pulsations associated with a falsely low oxygen saturation measured by pulse oximetry.

Venous pulsations are thought, but to our knowledge have never been demonstrated, to result in underestimation of oxygen saturation measured by pulse oximetry (SpO2); however, to our knowledge, this has never been demonstrated. A patient with ischemic cardiomyopathy requiring intra-aortic balloon counterpulsation (IABC) had to withstand a temporary cessation of IABC (period I), during which she had marked central venous pulsations and a pulse oximeter bias of -18%. After IABC was reinstituted (period II), the venous pulsations disappeared and the bias was reduced to 0%. Cardiac output, systemic vascular resistance, and temperature during both periods were comparable. Pulmonary vascular resistance, however, was much lower during period II. We postulate that the bias was caused by venous pulsations significantly contributing to the AC, or variable component, of light absorption.

Aged↗
PubMed1991

Intraaortic balloon pump entrapment.

Catheter entrapment is a rare complication of intraaortic balloon counterpulsation caused by the formation of hard blood clot within the balloon itself. We present two cases of intraaortic balloon pump entrapment seen at the University Hospital, Boston. This phenomenon usually presents as a limb threatening vascular emergency. The entrapped catheter becomes stuck fast within the iliac system during withdrawal of the device, occluding arterial flow at that level. The etiology of this phenomenon, and a proposed management scheme is discussed. Preoperative radiographic determination of the level of entrapment may be necessary. We feel it is necessary to control the abdominal aorta prior to removal of an entrapped intraaortic balloon.

Aged↗
PubMed2003

Haemodynamic considerations in the design of a skeletal muscle ventricle.

Skeletal muscle ventricles (SMVs) configured to operate as diastolic counterpulsators show promise as cardiac assist devices. In four pigs, SMVs were connected to the aorta by a single-limbed conduit and activated during every third cardiac diastole. During the assisted beats, mean diastolic aortic pressure increased by 30.3 +/- 2.2%, peak diastolic aortic pressure increased by 38.5 +/- 2.7%, the endocardial viability ratio increased by 42.3 +/- 3.4%, and mean left anterior descending coronary artery flow increased by 61.6 +/- 4.5%. Although there are major advantages to making the connection to the aorta by a single-limb conduit, the lack of separation between inlet and outlet means that such devices must be designed carefully to avoid thrombogenesis under chronic conditions. Design rules were developed for this configuration, based on earlier in vitro studies. They addressed the problem of stasis by promoting the development of a propagating vortex that travels the length of the ventricle and ensured proper exchange of blood with the circulation by limiting the volume of the connecting conduit. An SMV compatible with these rules was connected in a pig. At elective termination 1 week later, activation of the SMV increased peak diastolic pressure by 20.1% and reduced left-ventricular stroke work in the post-assisted beat by 10.1%. The SMV was free from thrombus.

Animals↗
PubMed2006

Treatment options for refractory angina in patients who are not candidates for revascularization.

Patients with refractory angina are those for whom medical therapy has failed to eradicate the angina completely and who have persistent symptoms that are stable but limit their activities of daily living. Approach to management must include the elimination of the secondary causes of this condition and maximum medical therapy, and if angina persists, the consideration of other strategies. Controversy exists regarding the value of transmural myocardial laser revascularization. Enhanced external counterpulsation is clinically effective in approximately 70% of patients. Spinal cord stimulation is not being used clinically in the United States. In the United States, it is still an investigational procedure that is currently being evaluated prospectively in a randomized trial. Ranolazine, an inhibitor of sodium-dependent calcium overload, may prove to be useful in patients with refractory angina.

Acetanilides↗