Abstract:
Wound closure apparatus is provided including a body having an elongated, lowermost force-transmitting surface operable to be placed in a proximal, external, wound-closing position on a patient, together with a force-exerting assembly coupled with the body and operable to exert a downwardly directed force serving to generate wound-closing pressure against the patient&#39;s tissue. The force-transmitting surface is preferably three-dimensionally asymmetric so that forces of different magnitude are exerted at different locations along the length of the surface. The apparatus is especially designed for the closure of wounds attendant to endovascular interventions, e.g., a femoral artery puncture wound incident to percutaneous cardiac intervention (PCI), and is capable of quickly effecting wound closure with a time-to-ambulation (TTA) of approximately 60 minutes, and with a very low complication rate.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a division of identically-titled application Ser. No. 13/421,253 filed Mar. 15, 2012, which is a continuation of identically-titled application Ser. No. 13/105,255 filed May 11, 2011, and also claims the benefit of Provisional Application Ser. No. 61/461,923, filed Jan. 25, 2011, and Provisional Application S/N 61,463,373, filed Feb. 16, 2011, all of which are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is broadly concerned with improved apparatus and methods for closure of wounds in the tissue of patients, and especially wounds attendant to endovascular interventions, such as percutaneous cardiac intervention (PCI,) wherein closure is defined as the time from removal of the catheter to ambulating the patient. More particularly, the invention is concerned with such apparatus and methods which employs a rigid wound-closing body adapted to be placed adjacent and along the length of the wound, together with a force-exerting assembly operable to create forces which generate relatively high pressures on the patient&#39;s skin and tissue adjacent the wound. In preferred forms, the rigid body has a three-dimensionally asymmetric lower force-transmitting surface so as to exert forces of different magnitudes at different locations along the force-transmitting surface. Also, the force-transmitting surface is preferably exerted substantially constantly and in a substantially time-invariant manner. 
         [0004]    2. Description of the Prior Art 
         [0005]    Endovascular interventions such as PCI are widely accepted as a practical treatment option for coronary artery disease. For example, femoral artery puncture is commonly used in endovascular diagnostic and interventional procedures. Alternately, access may be made via the right radial or brachial artery. Such procedures are now commonly performed on an out-patient basis. In the case of a femoral arterial intervention, a puncture wound is made with a cannula to create an oblique subcutaneous tract and a terminal arteriotomy, followed by placement of a sheath within the tract. A catheter is then threaded through the sheath and into the adjacent artery, so that access can be had to the coronary arteries. After the diagnosis or intervention is completed, the catheter is withdrawn, the sheath is removed, and steps must be taken to close the wound. Wound closure typically involves compression to control bleeding until hemostasis occurs. Ideally, wound closure serves to minimize blood loss, effect hemostasis, and render the patient ambulatory in a relatively short period of time. 
         [0006]    Poorly executed wound closures may give rise to complications which are costly, increase hospital stays and affect morbidity. For example, inadequate hemostasis can lead to significant blood loss, patient discomfort, vessel occlusion, thrombosis, formation of arteriovenous fistula, and pseudoaneurysm requiring surgical intervention and/or steps to avoid infections. Complications at the access site due to arterial cannulation occur in 1%-5% of cases, but may be as high as 14% with some interventional procedures. 
         [0007]    Traditionally, wound closure has been a manual operation where a physician or nurse used manual hand pressure, using either one or two hands. One-handed manual pressure is usually carried out over a period of 30 minutes with a time to ambulation (TTA) of 4-6 hours. Two-handed manual pressure (often referred to as the “gold standard” of wound closure) ideally achieves optimal wound closure. In this technique, the healthcare professional&#39;s left hand exerts a semi-occlusive pressure upstream (closer to the heart) of the arteriotomy to moderate blood pressure fluctuations and to reduce the mean blood pressure from the heart without denying blood flow downstream. The professional&#39;s right hand holds an occlusive pressure over the arteriotomy, tract, and insertion site. This is continued for a period of approximately 30 minutes. However, in actual practice, there are a number of significant problems. For example, manual pressure that is too firm does not allow sufficient clotting factors to accumulate at the arteriotomy. Moreover, manual pressure along the tract varies because the tips of the four fingers of the right hand are not flat. Even more important, the person exerting manual pressure can tire during the 30-minute holding time, or the fingers may move or may not be placed properly. The person may also temporarily stop the application of pressure to examine the wound, causing a disruption of the maturing clot. Finally, different body types present different manual pressure issues, e.g., if the panniculus intrudes on the person&#39;s left hand, pressure variations may be induced as the patient breathes and the panniculus moves. TTA for this two-handed procedure is again normally 4-6 hours. 
         [0008]    Manual techniques can be supplemented with use of applied hemostasis adjuncts, which reduce the time to hemostasis (TTH) to 5-6 minutes, but do not lower TTA because there is no force on the arteriotomy after hemostasis is achieved. Manual pressure may also be supplemented with external devices, such as C-clamps or sand bags. These combined techniques have many of the same problems as straightforward manual pressure closures, and the external devices may be difficult to deploy on obese patients. Thus, while manual procedures are of long standing, they are deficient in that they can be tiring, require careful training, and represent inefficient use of the time of valuable medical personnel. 
         [0009]    Other closure techniques involve use of an intra-arterial anchor giving a TTH of about five minutes and a TTA of about 2-3 hours. Drawbacks of these procedures include a maximum French size of 8 Fr and the fact that the anchor and collagen plug must be left in the body for up to 90 days. Suture-mediated intra-arterial anchor techniques have also been used, but these are deficient in that the sutures remain in the body until absorbed, and nonetheless require that the anchor and plug be left in the body for an extended period. Finally, intra-tract closure has been used where the arteriotomy is mechanically stretched and then “boomerangs” back to an 18-gauge needle diameter. In these procedures, a heparin-neutralizing drug is deployed within the wound tract, and manual pressure is still required to close the 18-gauge needle hole. 
         [0010]    In recent years, new, larger interventional devices of up to 20 Fr are being used to perform tasks like operations within the heart itself. No existing closure device is indicated for these large interventions, and resort must be had to manual pressure or surgical techniques to close the large wounds. 
         [0011]    In response to these problems, various specialized vascular closure devices (VCDs) have been proposed, such as the device disclosed in U.S. Pat. No. 5,307,811 and commercialized under the designation “FemoStop.” While these and other VCDs have achieved widespread use, no prior VCD has fully solved the problems inherent in wound closures. Dauerman et al. ( J AM COLL CARDIOLL.  2007; 50 (17) Elsevier Science)—“Vascular Closure Devices: The Second Decade” described an ideal VCD:
       The patient factors influencing closure success notwithstanding the “ideal” closure device remains to be developed. What would this device look like? 1) A single device capable of providing successful closure for all patient and success site anatomical variations; 2) an atraumatic device without a foreign body or vascular alteration of the femoral artery; and 3) a simple-to-use device with &gt;95% procedural success and low cost.       
 
         [0013]    The prior art uses the terms “pressure” and “force” loosely. A person exerting force through small fingers would apply more pressure than a person exerting the same force with larger fingers. A further complication is that the heart is beating, making the pressure (sum of internal and external pressure) variable. What is critical is controlling blood flow. If there were no flow restriction, the arteriotomy would leak, resulting in a hematoma. If there were complete flow restriction, then the downstream extremities would be starved of oxygen and the arteriotomy would be starved of necessary clotting factors. Hence, the ideal VCD is one in which flow is restricted, but not excessively. 
         [0014]    Accordingly, there is an unfulfilled need in the art for a simple-to-use VCD which closely mimics “gold standard” manual wound closure, has a complication rate of &lt;1%, can be used on all types of patients, gives very low TTH and TTA values, and does not involve residual drugs, sutures, or anchoring devices. 
       SUMMARY OF THE INVENTION 
       [0015]    The present invention overcomes the problems outlined above and provides VCDs and corresponding methods which have many outstanding features. For example, preferred embodiments of the invention used in the context of arterial PCI procedures are characterized by:
       a TTA on the order of 60 minutes for diagnostic PCI procedures;   a complication rate of &lt;1%;   atraumatic, essentially painless wound closure with no residual foreign materials in the wound or vascular alterations;   targeted asymmetric tissue pressures, with a larger non-occlusive pressure applied upstream of the arteriotomy to lower the patient&#39;s blood flow, with decreasing pressures downstream of the arteriotomy;   substantially time-invariant wound closure pressures on the tissue;   skin inversion adjacent the wound by means of a Z-stitch suture together with a rigid, force-transmitting surface including a transverse section positioned above the arteriotomy and generating force of greater than about 20 lbs., but not greater than the suture-rupturing force, and an obliquely oriented, axially extending section, which generates decreasing pressures downstream of the arteriotomy;   secondary wound closure force through use of an adhesive sheet stretched over the device and adhered to the patient&#39;s skin on either side of the site;   virtually no blood loss during wound closure;   different sheath sizes, blood chemistries (e.g., INR&gt;1.5, or the presence of blood thinners), and degrees of intervention can be accommodated by increasing the closure time;   a device cost on the order of $100;   wound closure procedure is typically learned with less than ten diagnostic procedures.       
 
         [0027]    In the ensuing description, the methods and apparatus of the invention are described with particular reference to wounds incident to an arterial intervention procedure. However, it should be understood that the invention is equally applicable to other types of vascular vessel procedures where a wound includes an opening in a non-arterial vascular vessel, such as a venous vessel. 
         [0028]    In one aspect of the invention, apparatus is provided to close a wound in a patient&#39;s tissue where the wound presents an insertion site and an elongated, obliquely oriented tract extending into the patient&#39;s tissue and in communication with the insertion site. Such apparatus comprises a body having an elongated, rigid force-transmitting surface and operable to be placed in an external wound-closing position with the force-transmitting surface proximal to the patient&#39;s skin, adjacent the wound and in general axial alignment with the tract. A force-exerting assembly is coupled with the body and is operable to exert forces of different magnitudes at different locations along the length of the force-transmitting surface in order to close the wound. In preferred forms, the force-transmitting surface is three-dimensionally asymmetric, and comprises first and second, preferably coplanar, surface sections having different force-transmitting areas respectively. Also, a third force-transmitting surface is provided which bridges the first and second surface sections and is generally T-shaped in configuration, presenting an elongated segment and a segment transverse to the elongated segment. Desirably, the elongated segment is obliquely oriented relative to the first and second surface sections. The force-exerting assembly is operable to exert a force which generates a force on the tissue of at least about 10 lbs., and more preferably at least about 20 lbs. 
         [0029]    The overall force-exerting assembly also includes structure for securing the body to the patient&#39;s tissue, and a mechanism including a shiftable component for generating a mechanically-derived force through the force-transmitting surface. Such securement structure preferably comprises a suture passing through the patient&#39;s tissue and tied to the body to hold the body in the wound-closing position. The suture may be in the form of a known Z-stitch suture which serves to invert the patient&#39;s skin at the wound site. The mechanism is preferably in the form of a biasing structure including at least one (and more preferably two) spring(s). Secondary forces may be generated by means of an adhesive sheet stretched over the device and adhered to the patient&#39;s skin on opposite sides of the wound site. 
         [0030]    Advantageously, the force-exerting assembly is designed to exert a substantially constant and time-invariant force through the force-transmitting surface; this, coupled with the preferred asymmetric force application serves to reduce the patient&#39;s blood pressure and flow within the artery and especially at the arteriotomy. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]      FIG. 1  is an exploded, upper perspective view of the preferred wound-closing apparatus of the invention; 
           [0032]      FIG. 2  is an exploded, lower perspective view of the preferred wound-closing apparatus of the invention; 
           [0033]      FIG. 3  is a side elevational view of the fully assembled apparatus; 
           [0034]      FIG. 4  is an end view of the fully assembled apparatus; 
           [0035]      FIG. 5  is a side view in partial vertical section illustrating the base portion of the apparatus, with the force-exerting springs in the released position thereof; 
           [0036]      FIG. 6  is a vertical sectional view taken along the line  6 - 6  of  FIG. 5 ; 
           [0037]      FIG. 7  is a vertical sectional view taken along the line  7 - 7  of  FIG. 5 ; 
           [0038]      FIG. 8  is a side view in partial vertical section illustrating the base portion of the apparatus, with the force-exerting springs in the cocked position thereof; 
           [0039]      FIG. 9  is a vertical section view taken along the  9 - 9  of  FIG. 8 ; 
           [0040]      FIG. 10  is a vertical section view taken along the line  10 - 10  of  FIG. 3 ; 
           [0041]      FIG. 11  is a top view illustrating a catheter sheath positioned within a wound attendant to a vascular procedure, and further illustrating the first step in the preferred method of the invention wherein a Z-shaped stitch has been created with a suture in the patient&#39;s tissue; 
           [0042]      FIG. 12  is a sectional view of the wound, sheath, and suture depicted in  FIG. 11 ; 
           [0043]      FIG. 13  is a top view illustrating the next step in the preferred method wherein the ends of the suture are tied to define an X-shaped stitch over the patient&#39;s skin; 
           [0044]      FIG. 14  is an end view in partial section illustrating the next step in the preferred method wherein the X-shaped stitch is tightened to invert the patient&#39;s skin adjacent the wound opening and the base of the apparatus is pressed downwardly over the stitch and wound opening; 
           [0045]      FIG. 15  is a sectional view of the steps depicted in  FIG. 14 ; 
           [0046]      FIG. 16  is a top view of the steps illustrated in  FIGS. 14 and 15 , with the apparatus base illustrated in phantom and also showing withdrawal of the catheter sheath from the wound tract; 
           [0047]      FIG. 17  is a top view of the next step of the method wherein the ends of the suture are passed around the rotatable operator forming a part of the apparatus base and knotted; 
           [0048]      FIG. 18  is a sectional view illustrating the position of the apparatus base and operator after the tying and knotting step illustrated in  FIG. 17 ; 
           [0049]      FIG. 19  is a view similar to that of  FIG. 18 , but illustrating the operator rotated to allow the force-exerting springs of the base to move from the cocked to the released position thereof so as to close the wound tract and reduce blood flow through the patient&#39;s artery adjacent the wound arteriotomy; 
           [0050]      FIG. 20  is a side view of the installed apparatus with a cover secured to the base and with a stretch of adhesive passed over the cover and secured to the patient&#39;s tissue on opposite sides of the wound and apparatus; 
           [0051]      FIG. 21  is a vertical sectional view of the fully installed apparatus illustrated in  FIG. 20 ; 
           [0052]      FIG. 22  is a top view of a preferred additional method step wherein a dam is placed around the wound opening and the sheath, and a hemostatic powder is deposited within the confines of the dam and over the wound opening; and 
           [0053]      FIG. 23  is a top view of the condition of the patient&#39;s tissue after wound closure and with the patient ambulatory. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The Preferred Wound Closure Apparatus 
       [0054]    Turning now to the drawings, apparatus  30  operable to close a wound in a patient&#39;s tissue is illustrated in  FIGS. 1-4 . The apparatus  30  is particularly designed for closure of wounds attendant to an endovascular (i.e., arterial or venous) intervention involving, e.g., a femoral artery puncture where the wound presents an insertion site, an elongated, obliquely oriented tract extending into the patient&#39;s tissue and communicating with the insertion site and an arteriotomy. Broadly speaking, the apparatus  30  includes a force-transmitting body  32  having a force-exerting assembly  34  together with a removable cover or “hat”  36 . 
         [0055]    As used herein, terms such as “upper” and “lower,” “top and “bottom,” and “downwardly” and “upwardly” and the like are used for convenience and because of the fact that the apparatus  30  is normally positioned in an upright orientation on a patient with the cover  36  being directly above the body  32 . However, if the apparatus  30  were to be placed in a different orientation (e.g., sideways) the cover  36  would nonetheless be deemed to be above the body  32 , and the above terms are intended to embrace all such different orientations. 
         [0056]    In more detail, the body  32  is of rigid unitary construction and is formed of an appropriate synthetic resin material. The body  32  has first and second, axially aligned cup-like sections  38  and  40 , each with an arcuate, upstanding sidewall  42 ,  44 , a bifurcated, rectilinear end wall  46 ,  48 , and a bottom wall  50 ,  52  serving to interconnect the section  38 ,  40 . A pair of grooves  54  and  56  are provided between each of the end wall bifurcations as best seen in  FIG. 2 . The bottom walls  50 ,  52  are configured to present first and second substantially flat and coplanar force-transmitting sections  58  and  60 ; it will be observed that the area of section  58  is smaller than that of section  60 , and this is important for purposes to be described. 
         [0057]    A protruding, downwardly extending segment  62  bridges and is integral with the bottom walls  50 ,  52  and presents a lowermost, generally T-shaped third force-transmitting surface  64  which bridges the sections  38  and  40 . The surface  64  presents an elongated, obliquely oriented and progressively tapered segment  66  extending from the end of bottom wall  52  to a point below bottom wall  50 . Another surface segment  68  is generally transverse to the elongated segment  66  and is substantially centrally located below bottom wall  50 . The segment  62  further includes a generally U-shaped sidewall  70  extending downwardly from the bottom walls  50 ,  52  of the sections  38 ,  40 . 
         [0058]    It will be appreciated that the body  32  presents an overall force-transmitting surface  72  made up of the force-transmitting sections  58 ,  60 ,  64 , and  68 . This surface  72  is three-dimensionally asymmetric owing to the fact that the area of first surface section  58  is less than that of the second surface section  60  (so that the overall surface  72  is asymmetric in a fore-and-aft direction), and because of the fact that the inclined surface segment  66  and transverse surface segment  68  are positioned below the first and second sections  58 ,  60  (so that the overall surface  72  is asymmetric in a vertical direction). Moreover, the inclined segment  66  provides an increasing and progressive force gradient from the second surface section  60  to the transverse segment  68 . 
         [0059]    The sections  38  and  40  are each equipped with an upstanding, slotted, tubular member  74  or  76  which extend upwardly from the upper surfaces of the corresponding bottom walls  50 ,  52 . As best seen in  FIGS. 5 and 8 , an elongated, downwardly extending cylindrical opening  78  is formed in bottom wall  50  and protruding segment  62  directly beneath and coaxial with the tubular member  74 . Likewise, a shorter, downwardly extending cylindrical opening  80  is provided directly beneath and coaxial with tubular member  76 . Each of the openings  78 ,  80  has a plurality of elongated, upright, circumferentially spaced apart, inwardly extending, integral ribs  82 . 
         [0060]    The configuration of the tubular members  74 ,  76  is identical, and therefore only the construction of member  74  will be described in detail. Specifically, member  74  has an upstanding sidewall  84  with a pair of specially configured and opposed slots  86  formed therein. The sidewall  84  is reinforced by means of external gussets  88  and braces  90 . Each slot  86  includes a lowermost, substantially frusto-circular portion  92 , an intermediate upright portion  94 , and an uppermost, inwardly extending lip portion  96 . 
         [0061]    The force-exerting assembly  34  generally includes a pair of identical, helically coiled springs  98 ,  100  respectively housed within a corresponding tubular member  74 ,  76  and supported therein by means of the adjacent upstanding ribs  82 . The overall assembly  34  further includes an elongated, axially rotatable paddle-like operator  102 , which extends fore and aft and is received by the opposed slots  86 , so that the operator extends through and is supported by both of the tubular members  74 ,  76  and engages the springs  98 ,  100 . The operator  102  is likewise formed of synthetic resin material and includes a central segment  104 , a pair of identical, elongated, slotted, oval-shaped segments  106  and  108  on opposite sides of the central segment  104 , and fore-and-aft segments  110 ,  112 . 
         [0062]    Referring to  FIG. 5 , it will be observed that the central segment  104  is cylindrical in configuration and has a central, peripheral, suture-receiving groove  114  formed therein. The oval segments  106 ,  108  are situated within the tubular members  74 ,  76  and have major axes  116  and transverse, minor axes  118  ( FIG. 6 ). The fore end segment  110  has a rounded outer edge, whereas the corresponding aft end segment  112  has a recessed trailing edge. In this fashion, the operator  102  has an arrow-like shape along the length thereof. 
         [0063]    The operator  102  serves to allow selective compression of the springs  98 ,  100  so as to maintain the springs in a cocked position as best seen in  FIGS. 8 and 9 . Upon 90° rotation of operator  102 , the springs  98 ,  100  are released to a force-exerting position illustrated in  FIGS. 5-7  and  10 . In more detail, if it is desired to cock the springs  98 ,  100 , the operator  102 , in the  FIG. 5-7  position where the major axes  116  are upright, is pressed downwardly through the upright portions  94  of the slots  86  until the bottom peripheries of the oval segments  106 ,  108  engage the bottoms of the frusto-circular portions  92 . Thereupon, the operator  102  is rotated 90° in either direction so that the major axes  116  are substantially horizontal and the oval segments  106 ,  108  are captively retained by the frusto-circular portions  92 . When it is desired to release the springs  98 ,  100 , this operation is reversed, i.e., the operator  102  is rotated 90° until the major axes are again upright. The springs  98 ,  100  then urge the operator  102  upwardly to the  FIGS. 5-7  position, with the lip portions  96  of the slots  86  serving to retain the operator  102  within the slots  86 . 
         [0064]    The cover  36  includes an uppermost wall  120  which is gently arcuate in cross-section and presents an upper surface  122  and a lower surface  124 . A pair of depending, slotted tubular members  126 ,  128  extend from bottom surface  124  and are in alignment with the tubular members  74 ,  76 . The members  126 ,  128  are identical, and therefore only member  126  will be described in detail. As best seen in  FIGS. 1 ,  2 , and  4 , the member  126  includes a sidewall  130  with a pair of opposed slots  132 . Each slot  132  includes an uppermost arcuate portion  134  and a substantially rectilinear portion  136 . The tubular members  126 ,  128  are of slightly larger diameter than the corresponding tubular members  74 ,  76 , allowing the cover  36  to be positioned over body  32  and pressed downwardly over the tubular members  74 ,  76  to assume the position depicted in  FIGS. 3-4 . It will be observed in this respect that the slots  86  of the tubular members  74 ,  76  are in substantial alignment with the slots  132  of the tubular members  126 ,  128 . 
       Preferred Method of Use of the Wound Closure Apparatus 
       [0065]    The preferred method of using the apparatus  30  is depicted in  FIGS. 11-23 , in the context of the closure of a femoral artery puncture wound  138  ( FIG. 12 ). It is to be understood, however, that the ensuing discussion is exemplary only, and that the invention can be used in virtually every type of endovascular arterial or venous intervention. 
         [0066]    The wound  138  is in the groin tissue  140  of a patient and includes an insertion site  142 , an elongated, obliquely extending tract  144  extending from insertion site  142  and terminating at an arteriotomy  146  in the femoral artery  148 . A conventional catheter sheath  150  is positioned within the tract  144  in order to permit an endovascular procedure using a catheter (not shown). When the procedure is completed and the catheter removed, it is necessary to promptly close the wound  138  during removal of the sheath  150 , while minimizing any blood loss and rendering the patient ambulatory in as short a period as possible. 
         [0067]    In order to facilitate the description of the preferred wound closure technique, the direction towards the patient&#39;s heart is denominated as “north,” whereas the direction leading away from the heart is denominated “south.” Correspondingly, transverse directions are denominated as “east” and “west,” respectively. Accordingly, it will be observed that the tract  144  extends from the insertion site  142  to the arteriotomy  146  in a generally northerly direction. 
         [0068]    In the first step of the wound closure procedure, the endovascular physician creates a Z-stitch  154  ( FIGS. 11-12 ) in the patient&#39;s tissue  140  by passing a suture  156  through an entrance  158  east of the artery  148  and south of insertion site  142 , an exit  160  west of artery  148  and south of insertion site  142 , an entrance  162  north of insertion site  142  and east of artery  148 , and finally an exit  164 . The end of the suture  156  adjacent entrance  158  is then clipped. The stitch  154  thus includes exterior suture stretches  166  and  168 , embedded suture stretches  170  and  172  above artery  148  at a depth of less than about one-half inch, and an obliquely extending exterior stretch  174  extending between the exit  160  and entrance  162 . 
         [0069]    In the next step ( FIG. 13 ), the exterior suture stretches  166  and  168  are crossed and interconnected by folding the stretches over each other, thereby creating an X-stitch  176  with a central suture fold  178 , and with the free ends  166   a ,  168   a  of the exterior suture stretches  166 ,  168  extending westerly and easterly, respectively. Preferably, the suture fold  178  is positioned in very close proximity or over the insertion site  142 . 
         [0070]    The next step ( FIGS. 14-18 ) requires two health care providers and generally involves tightening of the X-stitch  176  while the force-transmitting body  32  of apparatus  30  is positioned atop wound  138  with application of a downwardly directed force, and the sheath  150  is removed. In detail, one care provider grasps the free suture ends  166   a , and  168   a , and pulls these in an easterly and westerly direction, respectively. This serves to tighten the suture while inverting the patient&#39;s skin tissue, as illustrated by numeral  180 , at the region of the insertion site  142 . That is, uninvolved, parallel peripheral tissue is forced upwardly, while the central tissue adjacent the wound is pushed downwardly over the entire insertion site  142 , tract  144 , and arteriotomy  146 . The inverted tissue in cross-section thus resembles an M in shape. 
         [0071]    Once the skin is inverted, the second provider presses body  32  (which is in the spring-cocked position thereof) downwardly into the patient&#39;s tissue  140 , while withdrawing the sheath  150 . In particular, the body  32  is located in general north-south alignment with the artery  148 , such that the force-transmitting surface sections  58  and  68  are above and north of insertion site  142  and arteriotomy  146 , with the oblique section  64  over the suture fold  178 , and with the rearmost portion of surface section  60  located south of the insertion site  142 . As the body  32  is held in this position, the first provider, while still maintaining tension on the suture free ends  166   a  and  168   a , pulls the ends upwardly through the body grooves  54  and over the central segment  104  of operator  102 , and forms a secure knot  182  at the top surface of the segment  104 . In this condition (see  FIGS. 17-18 ) the artery upstream of arteriotomy  146  is partially closed, whereas tract  144  and arteriotomy  146  are fully closed. 
         [0072]    In preferred practice, the suture ends  166   a ,  168   a  are pulled upwardly while avoiding any twisting prior to formation of the knot  182 . This avoids reduction in the burst strength of the suture ends. That is, if the ends are twisted prior to knotting, the burst strength of the suture ends is reduced and can induce premature failure of apparatus  30 . 
         [0073]    In order to establish and maintain a substantially constant and time-invariant wound closure force, the operator  102  is rotated 90° so that the springs  98 ,  100  are released to their force-exerting positions ( FIGS. 5-7  and  19 ). This serves to maintain the suture  156  in tension so as to firmly draw the body  32  into the wound-closure position while also maintaining a substantially even force based upon the strengths of the springs  98 ,  100 . Preferably, the tensile force exerted on the suture  156  is slightly below the burst strength thereof; thus, the tensile force on suture  156  should typically be 10-15% less than the suture burst strength. 
         [0074]    Next, the cover  36  is positioned atop body  32  by pressing the tubular members  126 ,  128  over the tubular member  74 ,  76  until the cover is firmly seated. At this point, a length of wide adhesive material  184  (e.g., 6×8 inches) is placed over the cover  36  with the ends of the material  184  being pulled downwardly and adhesively attached to the patient&#39;s tissue at east and west and north and south locations, respectively. This material  184  may be stretchable or non-stretchable, and if desired may be breathable. Placement of the material  184  serves to exert a secondary force through the body  32 , in addition to that exerted by the springs  98 ,  100 , while also stabilizing the apparatus  30  on the patient. Advantageously, the height of the apparatus  30  above insertion site  142  divided by the maximum east-west transverse dimension of the force-transmitting surface  72  is greater than 1. With this ratio, the vertical component of the force generated by the material  184  is increased, causing additional force to be applied over the entirety of the wound. 
         [0075]    As finally positioned, the apparatus  30  creates targeted, asymmetric tissue pressures from north to south. At the north, a larger, non-occlusive pressure is applied upstream of the arteriotomy  146  in order to lower the patient&#39;s blood pressure and blood flow at the downstream arteriotomy. The transverse surface segment  68 , positioned directly above the arteriotomy  146 , closely mimics a properly executed two-handed manual wound closure. The lesser tissue pressures created south of the arteriotomy  146 , owing to the decreasing force gradient generated through the oblique section  66 , and the greater surface area of southernmost section  60 , also are similar to such manual closure. 
         [0076]      FIG. 22  depicts another preferred aspect of the invention, namely the use of a compressible dam  186  having a central opening  188  over the wound. In particular, the dam is placed in surrounding relationship to the insertion site  142  and a hemostatic powder  190  is sprinkled into the opening  188  (about 0.3 g). This procedure is carried out prior to tensioning of the suture free ends  166   a ,  168   a , and placement of the apparatus  30  on the wound site, as previously described. Of course, the dam remains in place during the entire closure sequence, and is then removed after closure. The hemostatic powder  190  may be a cationic surfactant combined with a strong acid cation exchange resin, or a potassium ferrate/strong acid cation exchange resin. Preferably, the powder  190  is of the type described in U.S. Pat. No. 6,187,347. In another embodiment, a sheet of exudate-absorbing woven or non-woven hemostatic material (such as oxidized cellulose or chitosan) may be used in lieu of or in addition to the powder  190 . 
         [0077]      FIG. 23  illustrates the condition of the wound  138  at the completion of wound closure. After the appropriate closure time, the knotted suture  156  is cut and the apparatus  30  is removed from the wound  138 . It will be seen that the insertion site  142  is closed (clotted) with the suture openings likewise closed. If desired or needed, a hemostatic/antiseptic powder can be sprinkled over the insertion site and the suture openings to help prevent infections and inhibit oozing. Normally, no dressing is required, and the loose powder is merely brushed off the wound site. 
         [0078]    A significant advantage of the invention is that TTAs are substantially reduced. In the case of diagnostic procedures, TTAs on the order of 60 minutes are common, and with more complex interventional procedures, TTAs of 120 minutes are typical. In a pre-clinical study involving 100 patients with interventional procedures up to 12 Fr, the preferred apparatus of the invention closed the patients&#39; wounds with no complications and TTAs of less than 120 minutes 
         [0079]    The invention also is useful with seriously obese patients. With such patients, the panniculus descends to the femoral insertion site, interfering with normal deployment of closure devices. This restricts the space around the wound and the ability of the healthcare professional to properly apply manual closure pressure. However, in the present invention, pre-compression of the springs  98 ,  100  and latching them with the operator  102  allows the device to be aligned over the wound and the knot  182  tied. Thereupon, the operator  102  is rotated to release the springs, and the material  184  is applied. 
         [0080]    Those skilled in the art will appreciate that the preferred embodiment of the invention may be modified in many ways while still achieving the aims of the invention. For example, while identical springs  98 ,  100  are preferred, springs of different strengths and/or types may be used, e.g., flat and coiled springs. The springs may be attached to the lower body or the top cover of the apparatus, at the discretion of the designer. Additionally, the invention may be practiced without the use of the Z-stitch suture  156 . In this embodiment, a spring force is generated directly against the top cover by manually placing the cover in direct contact with the spring(s). Then an adhesive material or film  184  is brought over the cover and pressed downwardly to compress the spring(s) and hold the device in place by adhering the film to the patient&#39;s skin on either side of the wound  138 . Such an embodiment is useful, for example, on very thin elderly patients whose skin is so fragile that sutures are not effective to retain the device in place.